NEW TAMPA, Fla. (WFLA) — A rapper who was recently acquitted of double murder was arrested Wednesday for killing a pregnant mother in New Tampa, the Tampa Police Department said.

Detectives said they identified 25-year-old Billy Adams as the suspect in the homicide. Police said the arrest comes nine days after 22-year-old Alana Sims was found shot to death outside her car in the 10700 block of Pictorial Park Drive.

Police said Sims’ young son was found sleeping inside the car. According to authorities, the boy was unharmed and is now in the care of a relative.

Investigators said Adams and Sims were in a relationship. Sims was five months pregnant with what is believed to be Adams’ child.

Detectives said Sims’ believed she was going to a party to celebrate that Adams was found not guilty before she was shot to death.

Police said they believe Adams’ motive for the shooting was that he didn’t want the baby and Sims in his life.

When detectives talked to Adams, they thought something was wrong with his initial statements. They said other witnesses didn’t collaborate with his alibi either.

Investigators said video showed Adams’ car near the crime scene even though he denied being anywhere near there.

Police said Adams later admitted to killing sims to detectives. He was arrested at his parents house in New Tampa.

“Mere days after he was acquitted of a separate crime, our homicide suspect did the unthinkable when he killed an innocent woman and her unborn child,” said Interim Chief Lee Bercaw. “I hope this arrest brings some closure to the victim’s family who is mourning the loss of two loved ones. We are working with the State Attorney’s Office to ensure the suspect is prosecuted to the fullest extent of the law.”

Adams faces charges of first-degree murder and killing of an unborn child by injury to the mother.

“What this defendant did is unimaginable,” State Attorney Susan S. Lopez said. “Our thoughts and support are with the family members of these crime victims. Since the night of the murders, we have worked closely with TPD to arrest this killer. While we respect the verdict of the jury in the prior case, we disagreed with it and that is why we prosecuted him. We will continue to work with TPD to prosecute him for these latest crimes.”