Deputy Assembly Speaker Neil Cohen is being investigated for alleged possession of child pornography, according to two of his Democratic colleagues who said they brought the matter to the attention of law enforcement.

In a joint statement, Sen. Raymond Lesniak and Assemblyman Joseph Cryan (both D-Union) confirmed they alerted authorities to the possibility Cohen (D-Union) had child pornography on his computers.

"As the facts became apparent in our office, we notified the appropriate agency and will continue to assist in any way possible," Lesniak and Cryan said. "While it was our proactive steps that led to the investigation to this point, we are appalled at what has transpired."At least one of Cohen's computers from the Union Township legislative office the three lawmakers share was confiscated by the Attorney General's Office, according to three sources who have been briefed on the investigation. Two of the sources said a legislative staffer initially discovered the images, then notified Lesniak and Cryan. The sources declined to be identified because they were not authorized to discuss the ongoing investigation.

"Both of us have known Neil Cohen for more than two decades," Lesniak and Cryan said. "We know him as a compassionate, caring individual but if the allegations prove true, clearly there was a side to him neither of us knew. We have been instructed to not make any further comments regarding this very serious matter."

Sources said Cohen was under psychiatric care Thursday night. He could not be reached for comment.

Assembly Democratic spokesman Derek Roseman declined to comment. Attorney General Anne Milgram and spokesman David Wald did not return phone messages.

Cohen, 57, is in his 17th year in the Assembly, having served from 1990 to 1991 and continuously since 1994. He chairs the Financial Institutions and Insurance Committee and is one of seven deputy speakers. He also is a long-time member of the Legislature's Joint Committee on Ethical Standards.

Lesniak and Cryan reported the Cohen matter to authorities on Monday.

"We have been in constant touch with the appropriate authorities throughout the situation and will continue to follow the Office of Legislative Services guidelines and counsel in this matter," Lesniak and Cryan said.

A law enforcement source said material seized from the raid of Cohen's office has been turned over the State Police Official Corruption Unit. The source, who declined to be identified because he was not permitted to speak publicly about the case, said the State Police have not yet looked at any of the evidence.

Cohen practices law in Montclair with Sen. Nia Gill (D-Essex).

Among the more than 100 laws Cohen has sponsored is one that created a 24-hour hotline for members of the public to report computer crimes, including child pornography. He also co-sponsored a law that retroactively removed immunity from churches, schools and other charities that negligently hire employees who sexually abuse children.

He also supported measures to support stem cell research, provide health insurance for mammograms, restrict strip searches and expand eligibility for the Pharmaceutical Assistance for the Aged and Disabled program.

He was one of the leaders last year of the effort to save the life of Congo, a German Shepherd condemned as a vicious dog after mauling a landscaper. Congo was spared for that incident only to be destroyed by his owners last month after attacking a family member. Cohen's measure to provide greater protections to dogs accused of being vicious, dubbed "Congo's Law," is still pending.

Word of the development spread quickly through Cohen's district. Roselle Mayor Garrett Smith, a Democrat but longtime opponent of Cohen and his supporters in the Union County Democratic organization, said, "My phone started ringing off the hook. I hit the floor when I heard the news. I'm speechless. It's incredible -- if it's true. I don't know what to think."

"I know he's kind of like a loner...but I've had no indication of anything like that," Smith said.

Third Ward Councilwoman Cecilia Dallis Ricks, a former Board of Education member, local Girl Scout leader and longtime Cohen supporter, was "totally shocked."

Prior to his election to the Legislature, Cohen served as a Union County freeholder from 1988 to 1990. He was the Union County Democratic Chairman during 1991 and 1992.

Cohen, who is not married, graduated from Athens University in Alabama and Howard University School of Law in Washington, D.C. After a clerkship with a Superior Court judge, he began his legal career as a trial lawyer in the Middlesex County Public Defender's Office.

"Let me just give you one statement. This is how I feel. I have nothing but respect for Neil. I have no comment on any of the accusations," said Gleshia Givens, his chief of staff.

By Josh Margolin And Robert Schwaneberg, Star-Ledger Staff. Staff writers Susan K. Livio, Carly Rothman and Rick Hepp contributed to this report.