STERLING HEIGHTS (WWJ/AP) – A doctor says two of four suspected escorts found dead in Detroit in 2011 likely died from asphyxiation.

Dr. Francisco Diaz was the first witness to take the stand Wednesday at a court hearing to determine if James Brown of Sterling Heights will stand trial on four counts of first-degree murder.

READ MORE: Oxford Schools Superintendent Issues Statement After Tragedy In Texas

Diaz performed autopsies on the bodies of  24-year-old Demesha Hunt and 23-year-old Renisha Landers . He said he found no evidence of trauma but believes they died of asphyxiation — a lack of oxygen to the brain.

“What’s interesting about this case is James Brown is 6’10” and weighs 350 pounds,” reported WWJ Legal Analyst Charlie Langton. “And the testimony indicates that Brown may have sat on these women killing them, because there is no other evidence of trauma, or gunshots or stabbing or anything along those lines.”

Testimony on Wednesday also indicates that Brown’s DNA was found under the victims’ fingernails and blood was found in Brown’s house that matches the victims.

READ MORE: Michigan Senate Blocks Gun Storage Vote

The bodies of Hunt and Landers were found in separate car trunks in Detroit. The bodies of two additional women, Natasha Curtis and Vernithea McCrary, were found Christmas Day in the trunk of burning car. At least three of the four victims promoted themselves as escorts-for-hire on, which carries classified and personal ads.

Brown is charged in Macomb County, where the deaths are alleged to have occurred. He faces life in prison if convicted.

Catch up on this case

MORE: Detroit’s Most Horrific Crimes Of 2012

MORE NEWS: Detroit Pistons To Play Regular Season Game Against Chicago Bulls In Paris

(TM and © Copyright 2013 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2013 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)