A Denham Springs man accused of injecting his girlfriend with a lethal dose of heroin in July 2013 was sent back to jail Thursday after flunking two drug tests this week while awaiting trial on a second-degree murder charge.

State District Judge Don Johnson, at the request of East Baton Rouge Parish prosecutors, revoked Jarret McCasland’s bond and said he will remain behind bars until his trial. A trial date has not been set.

McCasland, 26, was arrested in October 2013 in the death of Flavia Cardenas, 19, and was released in May on $265,000 bond.

Assistant District Attorney Will Morris filed a motion to revoke that bond after McCasland was arrested in Baton Rouge in July on a count of simple battery. He posted a $2,500 bond on that count and was released the day after his arrest.

Johnson ordered McCasland to report for bond supervision in August.

Assistant District Attorney Robert Savage then filed another motion to revoke McCasland’s bond in the murder case after he was arrested in Livingston Parish in January on possession of the pain pill Hydrocodone.

At a hearing Thursday on the revocation motions, Johnson was informed by Amber Kepper with Criminal Justice Service — a bond supervision program — that McCasland tested positive for cocaine Monday and Wednesday.

The judge quickly revoked McCasland’s bond, and East Baton Rouge Parish sheriff’s deputies took him from the courtroom.

“You can’t get re-arrested and do drugs while out on bond for murder. It’s as simple as that,” Morris said afterward.

McCasland, who has pleaded not guilty in the murder case, faces an automatic sentence of life in prison if convicted as charged.

Louisiana lawmakers expanded the state’s second-degree murder statute in 1987, amid the crack cocaine epidemic in this country, to include offenders who distribute an illegal drug that is proven to be the direct cause of a user’s death, even when that person lacked specific intent to kill.

District Attorney Hillar Moore III has said the second-degree murder charge against McCasland is based on allegations the heroin was the direct cause of Cardenas’ July 26, 2013, death.

McCasland’s attorney, Rodney Messina, reiterated Thursday that cocaine and other substances besides heroin were found in Cardenas’ body after her death. The central issue in the case, he said, is whether the heroin in her system caused her death.

A witness told deputies McCasland administered cocaine and heroin to Cardenas at the witness’ home, according to court documents. The witness told sheriff’s officials Cardenas didn’t know how to inject herself with the syringe and relied on McCasland to administer the drugs.

Follow Joe Gyan Jr. on Twitter, @JoeGyanJr.