(AP) New Jersey Assemblyman Neil Cohenresigned from the Legislature on Monday, four days after it wasreported that he's under investigation for suspected possession ofchild pornography. The clerk of the Assembly received a one-sentence letter fromCohen just before 9:30 a.m. Monday. Cohen said his resignation iseffective immediately, but did not offer any explanation. Cohen has not been charged with a crime. Colleagues who use the same legislative district office as the57-year-old Democratic lawmaker said last week that they told lawenforcement authorities about images of child pornography found onhis computer. The Star-Ledger of Newark reported on Saturday, citing sourceswho were unnamed because they were not authorized to discuss thecase, that a staffer in Cohen's Union Township legislative officefound a printout of a photograph of a nude girl, possibly in herearly teens or younger. Cohen, an unmarried divorce lawyer, has served in the Assemblyin 1990-91 and continuously since 1994. He is regarded as among the most liberal and busy legislators,introducing 342 bills this legislative session - 94 more than anyother legislator. "Assemblyman Cohen was a respected legislator who dedicated hislife to the State House and whose legacy would have been great,"said Assembly speaker Joseph J. Roberts. "Unfortunately, all ofthat will now be forever overshadowed." "We sincerely hope he receives the help he desperately needs,"Roberts said. Cohen has been hospitalized for psychiatric treatment. It wasnot immediately clear Monday whether he was still in a hospital. He did not return a call to his cell phone Monday morning.