A 30-year-old Wahiawa man charged with sexually assaulting and robbing a 25-year-old woman Wednesday at a Wahiawa shopping mall bragged about the attack to his female roommates, who then tipped off police.

Police conducted surveillance at Tyrone Smith Jr.’s Lakeview Circle apartment Friday and arrested him.

Smith was charged Saturday with first-degree sexual assault, kidnapping and second-degree robbery. He made his initial appearance in court yesterday.

The victim told police she was walking down the stairs at the Wahiawa Shopping Center, 823 California Ave., when a man came up from behind her at 8 p.m. Wednesday, demanded money, sexually assaulted her and took her belongings.

According to court documents, Smith later told two roommates he robbed a girl at the mall.

Smith told one roommate he had "slammed the girl to the ground and took her iPod, a silver chain and a ring," a police affidavit filed in Honolulu District Court said.

Smith also described to the other roommate how he put his knee on the woman’s head and took her money and jewelry, the affidavit shows. The roommate also found a credit card in her trash bin with the victim’s name on it.

Smith and his girlfriend also showed a bank card with the name of the victim to the first roommate, the affidavit said.

Smith remains in custody at the Oahu Community Correctional Center, where he is being held in lieu of $500,000 bail.