The man who gunned down 13 people in an immigrant center thought police had harassed him for years, even spreading rumors about him and touching him in his sleep, and apparently was intent on killing people before returning "to the dust of the earth," according to a rambling letter in broken English mailed to a TV station the day of the massacre.

The letter's authenticity could not immediately be verified Monday, but the city of Binghamton said it was reviewing the material as "evidence in the investigation." The letter was mailed to News 10 Now, in Syracuse, and postmarked Friday, the day Vietnamese immigrant Jiverly Wong stormed into the American Civic Association and went on a rampage before killing himself.

"I am Jiverly Wong Shooting the people," the letter begins.

Click here for photos.

Click here for a link to the list of victims.

The letter was dated March 18, more than two weeks before the shooting. It included photos of Wong smiling with two guns, a gun permit and his driver's license. The envelope carried three stamps: two Purple Hearts and a Liberty Bell.

The letter ends with him saying he can't "accept my poor life," that he is taking on the job of a judge and will "cut my poor life." He writes "at least two people with me go to return to the dust of the earth."

Police speculated Wong, who was ethnically Chinese but was from Vietnam, was angry over losing a job and frustrated about his poor English skills.

"I am sorry I know a little English," the letter reads.

It indicates a delusional man obsessed with unidentified police he says taunted him and tortured him, even going into his room, watching him sleep and touching him while he slept. The letter says police stole money from his wallet and stopped their cars in front of him 32 times in efforts to make him crash into them.

"I never hit the car," the letter states.

In a statement, the city of Binghamton, which is about 140 miles northwest of New York City, said it was reviewing the letter but would release no further comment about it until a press briefing scheduled for Tuesday.

Police Chief Joseph Zikuski told the TV station police would be asking mental health professionals to analyze the letter. He said behavioral experts from the FBI suggested "something like this might happen."

"It's not a complete surprise to us whatsoever," he said.

News 10 Now said it received the letter Monday.

In staccato bursts, the letter writer strings together a tale of police harassment following him from California to New York.

"Many time from 1990 to 1997 at the day time ... cop exploit unknow English and went to my house knock the door for harass and domineer," it reads. "Of course during that time cop coined something was not true about me and spread a rumour nasty like the California cop."

Wong, 41, spent several years in California, where in 1992 he was arrested on a bad-check charge. It was in California, where he drove a truck, that he divorced his wife, Xiu Ping Jiang, in 2006. He returned to Binghamton the next year.

The writer expresses frustration over losing his job at a vacuum manufacturer.

"Right now I still get unemploment benefit of the company Shop Vac Endicott," he says. "New York State Department of Labor was cheat and unpaid from December 1st 2008 to December 28th 2008 I already claim weekly benefit from that date."

The letter contained photos of Wong sitting in what looks like an institutional kitchen. In one, he points a gun toward the ceiling. In another, he sits at a table holding a cup, two guns resting within inches of his left elbow. In a third, he stands in front of a kitchen island bar, bar stools behind him and his arms folded defiantly across his chest, a gun in each hand.

The package mailed to the TV station included Wong's pistol permit, which describes him as 5-foot-8 and 135 pounds. It lists six guns, four of which are crossed out: two Ruger .45-calibers, a Glock 9 mm and a Springfield 9 mm. Two Berettas are not crossed out: a 9 mm and a .45-caliber. Police say Wong used a 9 mm and a .45-caliber in the shootings.

The letter rambles disjointedly.

"Let talk about when I live in California," it reads. "Such as...cop used 24 hours the technique of ultramodern and camera for burn the chemical in my house. For switch the channel time ... For adjust the fan. For made me unbreathable. For made me vomit. For connect the music into my ear."

There are passages of pure politeness: "Please continue second page thank you," the writer instructs.

But the letter ends with dark foreboding.

"Any way I can not accepted my poor life. Before I cut my poor life I must oneself get a judge job for make an impartial with undercover cop by at least two people with me go to return to the dust of earth.

"Already impartial now..cop bring about this shooting. cop must responsible."

The letter, neatly written in capital letters, ends with: "And you have a nice day."