It’s been one month since Peter Braunstein allegedly posed as a firefighter and sexually assaulted a woman in Chelsea, and the police pursuit of him has now spread to Indiana and Illinois, the police commissioner, Raymond Kelly, told The New York Sun yesterday.

The New York Police Department is collaborating with other law enforcement agencies in the effort, he said.

Police were tipped off that Mr. Braunstein could be in one of the two states, police officials said. The lead came last week, around the same time that police were hunting for Mr. Braunstein in Ohio. The search in Ohio, where a former friend of the suspect lives, proved fruitless, authorities said.

Mr. Braunstein’s mother, Angele Braunstein, said she did not know why police would be looking for her son in the Midwest.

“I would be very surprised to hear he had friends anywhere,” Ms. Braunstein, 75, said by telephone from her Kew Gardens home, where her son lived off and on for 20 years.

Mr. Braunstein, who turns 42 in January, severed all ties with his friends, Ms. Braunstein said.

She could recall meeting only one of her son’s friends, Michael Doyle. Messrs. Braunstein and Doyle were the editors of “Imagine Nation: The American Counterculture of the 1960s and ’70s,” published by Routledge in 2001.

“I met Doyle once,” Ms. Braunstein said. “He was very nice.” She said she arranged and paid for a party at a restaurant to celebrate the release of the book. She said her son had a fondness for Jane Fonda and the British actress Helen Mirren, both of whom Mr. Braunstein interviewed for stories.

Police have been trying to catch Mr. Braunstein since Halloween, when he allegedly dressed up as a firefighter, started a couple of small fires in a 34-year-old woman’s apartment building, made his way into the woman’s home, and drugged her before sexually abusing her for close to 13 hours.

“It’s a month today,” Ms. Braunstein said yesterday. “The cops stopped calling me as often.”

Ms. Braunstein said she is not surprised that her son has managed to evade police for an entire month because “he’s brilliant.” She also said he “must’ve planned this whole thing.”

The last confirmed sign the Police Department has had of Mr. Braunstein was on November 2, when he used a MetroCard to access the subway system, police officials said. A day earlier he stayed at the Super 8 Hotel on West 46th Street following the alleged crime.

The paper trail went cold after that day because Mr. Braunstein stopped using the card. Police officials speculated that he might have read a published account disclosing that police were tracking him by its usage.

It is not clear how Mr. Braunstein has been supporting himself while eluding the police, but his mother said he earned a good wage because he worked very hard as a freelance writer.

Mr. Braunstein’s ordeal has proved taxing on his mother. “I have never been so stressed out in my life,” she said, adding that she has lost 8 pounds in 30 days. Her typically high blood pressure is down a bit due to medication, but she says she is exhausted.

Mr. Braunstein has had a long history of mental illness, his mother said. He was arrested in the spring for sending threatening e-mails to his ex-girlfriend, harassing her on the telephone at work and at home, menacing her with a knife, and e-mailing naked photographs of her to her co-workers, police sources and the criminal complaint said. Over the summer he pleaded guilty to menacing and received three years’ probation, five days of community service, and a final order of protection.

In October 2004, Mr. Braunstein overdosed in what may have been an effort to commit suicide, his mother said. Mr. Braunstein was admitted to the Jamaica Hospital emergency room at that time, a hospital spokesman confirmed.

Ms. Braunstein said she hopes police capture her son soon so he can receive the psychiatric help he needs. At the end of the day, Ms. Braunstein said, “he is my son, no matter what.”