“A lot can happen in 20 years,” a Suffolk County prosecutor said at the close of trial in a pair of 20-year-old rapes in Boston’s South End. “People’s memories fade, but the truth never changes.”

MICHAEL JOHNSON (D.O.B. 4/9/69), himself a South end resident at the time of the 1990 attacks, is charged with raping a 23-year-old woman in her Wellington Street apartment on April 10; raping a 24-year-old woman in her West Concord Street apartment on May 7; and attempting to rape that woman’s 30-year-old roommate during that same incident.

Johnson allegedly bound the first victim’s hands behind her back with a telephone cord and covered her face with a towel, preventing her from seeing his face. He was allegedly present when the second set of victims returned home late at night, turned out the lights, and attacked them from behind.

None of the victims was able to identify her assailant in the aftermath of the attack.

“There was no ID made in the heat of the moment,” Assistant District Attorney Leora Joseph said during her closing argument. “It’s better than an ID – it’s DNA.”

Johnson was identified in 2003, when DNA recovered from the victims’ rape kits matched each other and Johnson’s genetic profile, which had already been stored in a database. The match was made by Boston Police criminalists during a program that investigated unsolved cases with biological evidence that was newly-admissible in Massachusetts courts.

“These were two women unknown to each other,” Joseph said. “The attacks were two months apart. There were two different detectives and two different DNA analysts.”

Joseph produced a chart showing the DNA profiles developed from biological evidence in the two victims’ rape kits and from a buccal swab taken from the defendant.

“At every single location you have a match,” she said. “The defendant’s sperm in the first victim’s vagina. The defendant’s sperm in the second victim’s vagina …. It’s incontrovertible evidence of his guilt.”

After closing arguments, Judge Peter Lauriat began instructing the jury on the law. Jurors will begin deliberating after those instructions.

Joseph tried the case with Assistant District Attorney Barbara Joyce. Anne Kelly-McCarthy is the victim-witness advocate assigned to the case. Johnson is represented by attorney Bruce Carroll.