The suspected drug dealer convicted of arranging the 2005 slaying of a Bowie teenager because he mistakenly thought the girl had arranged for him to be robbed was sentenced to 15 years in prison Friday, authorities said.

McDonald Abraham, 27, had pleaded guilty to second-degree murder and related counts in the June 2005 slaying of 17-year-old Stacey Seaton, who was pregnant and 18 days away from her 18th birthday when she was shot in the back of the head in a wooded area near her home. As part of his plea for the 15-year sentence, Abraham agreed to testify against the man detectives believed to be the actual shooter, 26-year-old Jarvis Tyler.

Tyler was acquitted of all the counts against him at a trial last week. At that trial, Abraham testified that he hired Tyler to kill Seaton for $400 and two bags of marijuana because he suspected Seaton had set him up for a robbery.

In fact, Abraham’s suspicions about Seaton were wrong, prosecutors said. The man who robbed him testified that Seaton had nothing to do with it, prosecutors said.