LAFAYETTE — Michelle Steven lingered in a coma for 12 years before she eventually died from “devastating injuries” she suffered in a 1989 attack at the hands of her sister’s boyfriend, a prosecutor told a jury Wednesday during the trial of the accused killer.

Louis Joseph George, 49, is on trial for second-degree murder in Steven’s death.

Steven remained in a coma until she died at age 35 in September 2001.

Prosecutor Keith Stutes told jurors the attack occurred during a period of mourning for Michelle and Debra Steven, who had just lost their mother.

“That loss would be magnified when they found Michelle beaten, strangled and unconscious” inside her home on Cobb Road in Lafayette Parish, Stutes said.

George climbed in through a bathroom window and tried to force Steven to have sex with him, Stutes said.

When she refused, he attacked her, the prosecutor said.

Steven suffered trauma to her face and head, with multiple cuts on her face and a shattered left eye socket, Stutes said.

“There was blood everywhere,” he said.

Investigators also found a chair propped up outside the home beneath a bathroom window, which they believed was the attacker’s entry point, Stutes said.

George, who was living with Michelle’s sister, Debra Steven, became a person of interest in the case early on, Stutes said.

George had left Debra Steven’s home on the night of the attack and returned with an injury to his right hand, Stutes said.

George later gave conflicting statements about the injury, saying he hit it with a hammer and that he suffered the injury while working on a tin roof, Stutes said.

The injuries Michelle Steven suffered were consistent with someone who had been beaten with a fist, Stutes told jurors.

George was not arrested early on, though, because a crime-scene technician could not say with certainty whether fingerprints found at the scene belonged to George, Stutes said.

Stutes told jurors that fingerprint technology has vastly improved since then.

When the fingerprints were reexamined in 2003, they came back as a match, Stutes said.

George, who had been in jail on unrelated charges since 1997, was arrested in Steven’s death in 2007. The delay between the match on the fingerprints and the arrest was due in part to the lack of a cold-case division at the Lafayette Parish Sheriff’s Office. The case was reactivated in 2005 once the cold-case division was created.

George’s attorney, Harold D. Register, said his client was not arrested at the time of the crime because there was no evidence against him.

“They didn’t arrest him,” Register told jurors during his opening statement. “They let him go.”

Register said the fact that George’s fingerprints were on a window should not come as a surprise because George worked as a handyman and “was around there all the time.”

Register said scrapings taken from beneath Steven’s fingernails also did not match his client.

The state’s most important evidence is DNA in the form of a small stain found on the victim’s jeans, Register said.

“The key issue in this case is: Do you really believe DNA is all it is made out to be?” Register asked the jurors.

Six witnesses testified Wednesday, including Dr. Jack Hurst, a retired neurosurgeon who treated Steven after the attack.

Hurst said Steven suffered a closed head injury and that her injuries were a direct cause of her death years later.

If convicted, George will face an automatic life sentence.

State District Judge Edward D. Rubin is presiding over the trial, which is scheduled to resume Thursday.