CHANDLER, Ariz. -- Chandler police said Tuesday that a fourth sexual assault has been linked to a serial rapist accused of attacking teenage girls in their homes.

Police said the latest assault linked to the investigation occurred between 6 and 6:30 a.m. on June 4, 2006. The 12-year-old victim was assaulted in her home near Arizona Avenue and Pecos Road after her parents left for work.

Police said details of the attack were being withheld in order to protect the identity of the victim and the investigation.

Fear caused the girl to wait more than seven months before telling her parents about the attack, but evidence backs up the girl's story, investigators said.

Police said the evidence also links the girl's assault to three later sexual assault incidents involving four other girls.

Investigators say the rapist is a Hispanic man who targets teenage girls in single-parent homes after the parent has left for work.

He tells them there's an emergency to get into their homes, then attacks them, according to police.

The most recent assault occurred March 23.

"I think what's making it so hard is that he blends into the community," said Sgt. Rick Griner of the Chandler Police Department. "The description is so vague, it matches thousands of people in this area."

The man wore a brown hooded work coat, possibly a Carhartt brand, and tan work boots with fresh blue and white paint drops on them. He had a cell phone with a specific ring tone that combined bells and rings.

Griner encouraged all employers who hire painters, construction workers and landscapers to examine employee records and time cards to see if anyone who bears a physical resemblance to the rapist was absent or late for work on the mornings of the assaults on Jan. 16, Jan. 31 and March 23.

Chandler police also encouraged parents and guardians of young girls to create open lines of communication about sexual offenses and physical boundaries in order to prevent future attacks.

Investigators urged residents to call in unreported incidents.

Police said they have reason to believe that some residents may have information that could help the case but that hasn't been reported because the residents thought it was unimportant.

Anyone with information about a possible suspect is asked to call Chandler police at 480-782-4130 or Silent Witness at 800-343-TIPS.

Silent Witness is offering a $10,000 reward.

CBS 5 News has learned that police have received more than 500 calls or tips and they've taken DNA swabs from possible suspects matching the description, but so far no match.