A third person was arrested Wednesday in the deaths last month of a pregnant teenager and her boyfriend in what San Antonio, Texas, police have said appeared to be a botched drug deal.

Myrta Romanos, 47, is accused of altering, destroying or concealing a human corpse, abuse of a corpse and tampering with evidence, Lt. Michelle Ramos said.

Police say she is the stepmother of Christopher Preciado, 19, who has been charged with capital murder in last month’s deaths. Preciado’s father, Ramon Preciado, 53, was also charged with abuse of a corpse.

Romanos was in handcuffs and ignored a hail of questions from reporters about her possible involvement Wednesday afternoon as she was escorted into a police car. Police earlier Wednesday provided a different spelling for Romanos.

It was not immediately clear if she had secured an attorney Wednesday afternoon.

In addition to capital murder, Christopher Preciado is also accused of abuse of a corpse and altering, destroying or concealing a human corpse, according to court records. Ramon Preciado is also charged with aggravated assault with a deadly weapon, evading arrest and altering, destroying or concealing a human corpse, court records said.

Savanah Soto, 18, and Matthew Guerra, 22, were found dead inside his Kia Optima the day after Christmas in a parking lot of an apartment complex, police said.

They had been shot in the head, authorities said. Leon Valley police said that when Soto disappeared, she was past her delivery date and that her family had contacted San Antonio police because she missed “an essential medical appointment.”

Police said that detectives had been seeking a third suspect since the earlier arrests, but officials waited to make the third arrest until they could collect the proper evidence and present the best case to prosecutors, Ramos said.

Surveillance video shows that Romanos was “involved the night of the murder,” Ramos said.

Security camera video police released after the bodies were found showed a heavy-set person driving a dark Chevrolet Silverado and another driving Guerra’s Kia. The two appeared to speak to each other out of the vehicles before driving away in separate directions.

Romanos also admitted that the gun used in the slayings belonged to her, police said.

“We’re confident that there are no more suspects,” Ramos said.

Soto and Guerra were killed just before midnight Dec. 21, officials said, but they were not reported missing until Dec. 23. She was scheduled to be induced shortly before her disappearance.

She had planned to name The unborn child, who was also slain, Fabian, Soto’s family has said.

Police spoke with the families of Soto and Guerra after their bodies were found. According to an affidavit for an arrest warrant, investigators learned Guerra sold drugs and would post money and drugs on Instagram.

Police connected the suspect’s Silverado seen on security video to Ramon Preciado, who admitted driving his truck near where the Optima was found and said he was seen on the security video, the affidavit said. He also said he met his son who was driving Guerra’s Optima at the apartment complex, where it was later found.

Christopher Preciado told police that Guerra and Soto drove to his house, a few blocks from where the Optima was discovered, to sell him marijuana. His statements then were inconsistent with collected evidence, the affidavit said.

“Christopher claimed the male victim pointed a weapon at him and Christopher was able to manipulate the weapon resulting in the female being shot,” according to the affidavit. “Christopher then stated that … the weapon pointed at him again and he manipulated the weapon again resulting in the male victim being shot.”

On Wednesday, police said Romanos was seen on surveillance video leaving her home shortly after the slayings in the Silverado and then returning to her home with the two other suspects who were also inside the truck.

This article was originally published on NBCNews.com