Prosecutors investigating embattled St. Bernard Parish President David Peralta say they have evidence that he planned to extort his ex-wife with hundreds of sexually explicit photos and that he frequented more than 2,000 hard-core pornographic websites last year, many of which depicted forced sex, according to a court filing issued Thursday by the Louisiana Attorney General’s Office.

The 11-page document, filed in 34th Judicial District Court in Chalmette, was drafted to notify the court that prosecutors plan to introduce evidence of additional wrongs they believe Peralta has committed. They expect the new evidence will show Peralta’s alleged motive for the attack or perhaps will pave the way for new charges that may still be filed. A grand jury in St. Bernard is still considering additional criminal charges against the first-term parish leader, who was indicted there last year on a count of sexual battery.

“Evidence that (Peralta) enjoys watching such videos is evidence that it was his motive or intent to initiate the sexual assault and a direct contradiction to previous public statements that such sexual behavior was the victim’s idea or desire,” Assistant Attorney General Matthew Derbes wrote in Thursday’s filing. Investigators found Peralta visited more than 2,000 Web addresses tied to pornography when they examined his work and personal computer, both of which were confiscated during a July search.

All told, prosecutors believe the evidence shows Peralta “previously and subsequently engaged in other, similar crimes, wrongs or acts that are ... admissible for the narrative completeness of the offense.”

The filing also claims Peralta played a part in a suspension of his ex-wife, Sharon Schaefer, that was handed down while she worked for the parish in 2013; that he had “over 300” sexually explicit photos of Schaefer that he considered posting online or otherwise using against her; that a handwritten note was found in Peralta’s home on which he allegedly scrawled, “Your (sic) going to be a rape victim”; and that Peralta conducted thousands of searches for pornography, including “images or videos depicting forced sex, rape, bondage and rough sex.”

Peralta, a former New Orleans police sergeant, has faced mounting legal problems since Schaefer accused him of handcuffing, beating and raping her in their Meraux home in October 2013. Peralta’s defense has hinged on his insistence that the couple — still married at the time — occasionally engaged in “rough sex” and that he was simply fulfilling his wife’s “rape fantasy” that morning. Schaefer has denied asking her husband to “rape” her as part of a sexual game.

Reached by phone Thursday, Peralta declined comment on the allegations, citing a judge’s gag order on the case.

Looking ahead, prosecutors hope to use evidence outlined in Thursday’s filing to argue that Peralta was in fact the one who was interested in rough sex, that the incident was not consensual and that it happened when the couple was not on speaking terms. But it’s likely that retired Judge Frank Foil, who was appointed as an ad hoc judge to hear the case, will have final say on what, if any of it, is introduced in court.

To make their case that the couple was experiencing marital discord in late 2013, the filing points to an incident in which Schaefer, who worked as a paralegal for the parish, was suspended without pay and transferred to a different parish department. Thursday’s filing rehashes the episode through internal parish emails to show that Peralta had spoken out in favor of suspending his then-wife, despite an earlier Ethics Board opinion stipulating that he not get involved in her employment.

Prosecutors argue that the incident illuminates the true status of the couple’s relationship leading to the attack and that it “corroborates the victim’s statement that they were living in separate rooms and not having consensual intercourse of any kind in the weeks leading up to the sexual assault.”

The filing described Schaefer’s suspension as being retaliation for her making allegations that parish employees were gambling at work. Though it doesn’t offer substantive evidence that Peralta engaged in the gambling, the incident came to light amid the couple’s public divorce. At the time, parish officials largely brushed the incident aside and chalked it up to lunch bets and wagering on fantasy football.

But prosecutors likely will tap into Peralta’s Internet browsing history to show jurors that his interest in rough sex was more than meeting his wife’s desires. “His Internet history contradicts those claims and proves the defendant’s desire, motive and intent to not only initiate rough sex and bondage-type sexual activities, but the sexual assault of his wife (where she was handcuffed, tied to a ceiling via a rope, beaten and sexually assaulted) for which he was indicted,” the filing states.

The audit of his computer also turned up a letter that Peralta allegedly drafted last year to his attorney handling the divorce case. In it, he outlined his negotiation strategy for cutting down Schaefer’s demands for spousal support and property that she might seek in the split.

Peralta indicated in the letter that he had “over 300 pictures” of Schaefer taken during sexual encounters and that he had contacted a Web developer about creating a website to post them online, the filing stated.

He also claimed in the letter that he was considering pressing charges against Schaefer for falsifying public documents tied to the divorce but could be persuaded against it. “ ‘Should they become reasonable with their ultimate demands I would agree not to have her prosecuted,’ ” Thursday’s filing quotes Peralta as saying.

Meanwhile, if divorce talks dragged, Peralta hinted in the letter that he could — as parish president — drop Schaefer’s health insurance. “Thus, using his ability as parish president to have her terminated and/or have her health benefits terminated to obtain an advantage in his private divorce case is both malfeasance and abuse of power,” the filing stated.

Peralta also considered leveraging the explicit photos “as a means to extort the victim into caving to his demands in the divorce case,” prosecutors contend.

The filing notes that Schaefer received 33 anonymous emails last year amid the couple’s divorce proceedings. In one email, the sender made reference to forwarding the compromising photos to Schaefer’s family in Tennessee. The state’s review of Peralta’s computer allegedly turned up Internet searches for Schaefer’s father in the same city referenced in the emails.

Though mostly through innuendo, prosecutors contend in the filing that Schaefer told authorities Peralta “has a gambling problem.” That news emerged as Peralta’s campaign finance spending for 2014 became public this week, showing that he held several expensive meals in and around Gulf Coast casinos in recent months, which he billed as meetings with people close to his re-election campaign.

Peralta reported spending more than $35,000 in campaign money last year, according to a candidate’s report filed Feb. 12 with the state Ethics Board.

Among his more expensive items: a $405.99 “campaign strategy meeting” May 23 at Bogart’s Steakhouse at Hollywood Casino and Resort Gulf Coast in Bay St. Louis, Mississippi, and a June 4 “campaign meeting” at Besh Steak at Harrah’s New Orleans Casino for the exact same amount: $405.99. The report also included five meals at The Buffet at Harrah’s beginning in early October that totaled about $1,830. Four of the tickets again were for $405.99 and the fifth for $205.99.

Peralta was indicted in April by a grand jury in St. Bernard on one count of sexual battery in connection with the allegations by Schaefer. He pleaded not guilty and was released on a $20,000 bond. The case is expected to be tried in April.

In September, a grand jury in St. Tammany Parish charged him with one count of felony stalking for allegedly harassing Schaefer. He pleaded not guilty and posted a $35,000 bond. That case is set for trial in May.

Follow Richard Thompson on Twitter, @rthompsonMSY.