JACKSONVILLE, Fla. (AP) _ A 15-year-old has been convicted in the second of a series of rapes that police have attributed to the ''Riverside rapist.''

Robert Louis Roberson was convicted Wednesday of the Dec. 15 rape of a 21- year-old woman in the Riverside area of Jacksonville.

Roberson, being tried as an adult, was convicted Sept. 17 for the Dec. 14 rape of a 23-year-old woman.

He faces five more trials. Prosecutors have said they intend to try Roberson separately in seven attacks in a bid to send him to prison for life.

In the latest trial, the victim, now 22, testified that Roberson burst into her bedroom while she was breast feeding her 3-month-old baby. She said he pointed a gun at her and raped her three times.

Assistant Public Defender Charlie Cofer admitted in closing arguments that Roberson had attacked the woman.

''The question is: did he use a deadly weapon while committing sexual battery?'' the attorney asked.

Roberson was convicted of two counts of sexual battery with a deadly weapon, one of armed robbery and one of armed burglary.