In the days after Sylviane Finck Lozada disappeared in July 2011, detectives seized several items from the Brusly High School teacher’s home, including pieces of used duct tape and a sample of “suspected dried blood,” according to court filings.

Lozada’s whereabouts remain a mystery nearly two years after her family in Belgium lost contact with her. But previously undisclosed search warrant affidavits, filed several weeks after the woman’s disappearance, offer new details about the early days of the investigation.

East Baton Rouge Parish sheriff’s officials said they still want to talk with Lozada’s husband, Oscar A. Lozada, who returned to his native Venezuela with the couple’s daughter shortly before Sylviane Lozada was reported missing.

Authorities have said foul play is possible in the case based on evidence found inside the couple’s Springlake Drive home in East Baton Rouge Parish.

Oscar Lozada has not been named a suspect in the case, but investigators have questioned his behavior and his purchase of several five-gallon buckets and bags of concrete mix that are also missing. Authorities learned about that purchase — made days before he left the country — after finding a receipt from Lowe’s in Oscar Lozada’s vehicle, said Casey Rayborn Hicks, a Sheriff’s Office spokeswoman.

Oscar Lozada, who was 36 at the time of his wife’s disappearance, told detectives he was in Venezuela due to medical reasons, sheriff’s officials have said. But he asked a family friend in Prairieville to retrieve his vehicle from the Baton Rouge airport, sell it and send him the proceeds “because he and his daughter did not plan on returning to the United States,” according to an affidavit.

Oscar Lozada also told authorities his wife had left him for another man in Columbia, affidavits show. But detectives determined Sylviane Lozada “did not use her passport to leave the country as stated by her husband,” the court filings show.

“Personally, I would consider him suspicious under all the circumstances,” East Baton Rouge Parish District Attorney Hillar Moore III said of Oscar Lozada. “I’d like to know where he is and what he’s doing. But that’s just my personal opinion, and it has nothing to do with the case itself.”

Sheriff’s officials remain reluctant to discuss details of the case. Hicks would not comment on the suspected blood or other items found in the Lozadas’ home.

Aside from the duct tape and suspected blood — found on a window pane in the garage — investigators also seized two cardboard cylinders; a pair of pink panties; a used roll of duct tape; four “DNA swabs from the garage floor”; six diving weights; a roll of Kodak film; two Motorola cellphones; a “sink catch pipe and water sample” and hair from the catch pipe, an affidavit says.

Karen Wooley, a colleague and close friend of Sylviane Lozada and the person who reported Lozada’s disappearance to authorities, said the diving weights are not a surprising find because Sylviane Lozada and her husband were divers. Wooley, who was among the first people to walk through the Lozadas’ home after her friend disappeared, said she did not recall seeing any blood.

Wooley said she has begun to question the pace of the investigation.

“My question all along has been what are they doing?” Wooley said, referring to the authorities. “I think they are waiting for something to happen.”

Sheriff’s officials would not discuss their efforts to contact Oscar Lozada, saying the release of sensitive information could derail the investigation.

“Detectives would like nothing more than to have all the answers to give to friends, family and the public,” Hicks said. “But when working an ongoing investigation like this, investigators have to do what is best for the investigation.”

Sylviane Lozada’s family members, who live in Belgium, said they still trust sheriff’s officials to find the truth. They said they are in regular contact with authorities at the Belgian embassy. They also have been in contact with the Lozadas’ 6-year-old daughter, Angelina, whom they said is still with Oscar Lozada and doing fine.

“We are certain that the detectives are still working and doing their best,” Sylviane Lozada’s sister and brother-in-law, Ghislaine and Patrick Paquet, said through an interpreter.

Oscar Lozada’s decision to leave the United States has complicated the investigation, as sheriff’s officials say they still want to speak with him. Venezuela’s constitution prohibits the extradition of Venezuelan nationals.

George Ciccariello-Maher, an assistant professor of political science at Drexel University in Philadelphia, Penn., said that because Venezuela has unsuccessfully requested extraditions from the United States, “they will be unlikely to go out of their way to help a request from the U.S.”

The relationship between Oscar and Sylviane Lozada — who was 51 at the time of her disappearance — had been strained at times, authorities have said. She contacted authorities in December 2010 because Oscar Lozada had been throwing things during an argument and she wanted him to leave, sheriff’s officials have said.

Later that month, deputies were called to a local hospital after Sylviane Lozada told medical personnel her husband had pushed her down during an argument.

“He was more emotionally abusive than anything,” Wooley said.

Sylviane Lozada, who taught French and Spanish at Brusly, was reported missing July 18, 2011. Her family last contacted her on July 5, authorities said, one day before Oscar Lozada is believed to have purchased the buckets and cement mix.

U.S. Immigration and Customs Enforcement officials confirmed that Oscar Lozada flew to Venezuela with Angelina on July 9, 2011, according to court records. They were scheduled to return July 14 but did not, authorities said.

The same day, an unidentified family friend went to the Baton Rouge airport, picked up Oscar Lozada’s 2001 Nissan Xterra and drove it to his Prairieville home, according to an affidavit. The man’s wife called detectives after seeing a news account that authorities were searching for the vehicle, the affidavit says.

Linda Hooper-Bui, an associate professor in the Department of Entomology at LSU and a close friend of Sylviane Lozada’s, said Oscar Lozada has attempted to contact her twice since he left the country. In one message, Oscar Lozada wrote that “no one is missing” and that Sylviane Lozada “is not the sweet person” everybody thinks she is.

“You do have a very wrong concept about my person and so (do) the rest of the people speculating about this,” the message stated.

Hooper-Bui is one of many friends who have been impacted by Sylviane Lozada’s disappearance. Last month, about 300 people gathered at an event in Sylviane Lozada’s family home in Polleur, Belgium, to release white balloons and keep her memory alive, family members said.

“My head doesn’t know what to do with ‘missing,’” Hooper-Bui said. “It’s really hard to figure out what to do with it because there is no closure.”