SAN ANTONIO -- Prosecutors said a man on trial in connection with the 2006 slaying of an 18-year-old woman tried to cover up the crime by pouring steak sauce on the teenager.

The trial of Edward Campbell got under way Wednesday, with jurors hearing how Michelle Carrasco was stabbed, strangled and sexually assaulted before her death.

Prosecutors also allege that Campbell may have been trying to cover up DNA evidence in an unusual fashion -- by pouring steak marinade over the victim's body.

Defense attorneys counter that Carrasco was killed in self-defense.

Several investigators testified about what they found at the crime scene, including how Carrasco was killed.

"It was approximately four centimeters deep into the chest, which is only based on an estimate of the structure it went through," medical examiner John Steash said. "It went through the chest, tissue, the ribcage and whatever organs were hit.

"In this case, it entered the skin, the fat beneath the skin, the muscles, pericardium, the (sac) that holds the heart and it injured the heart."

Testimony in the murder trial is scheduled to continue Thursday morning. If convicted of murder, Campbell could face anywhere from five years to life imprisonment.