On July 13, 2010 Hamed Mirabdal received a manila envelope in the mail. When he opened it, he gasped.

Inside was his wallet, stolen from him four years earlier during a brutal assault in which he almost died.

There was a short note in the envelope. “Found this while gardening on San Lorenzo Avenue in North Berkeley.”

The signature was indecipherable, but the note was scribbled on stationary from Keller Williams, a national real estate chain. The address at the bottom of the paper was from an office in Pennsylvania.

Now Berkeley police have put out a public appeal for help in discovering who mailed that envelope. The wallet may be a linchpin piece of evidence in the upcoming trial of the two men accused of almost stabbing Mirabdal to death.

But police only have a few days to find the sender. The trial is scheduled to start in Alameda County Superior Court on Wednesday Sept. 1. The wallet cannot be introduced into evidence unless the prosecution can show the court who sent it, according to Det. Emily Murphy of the Berkeley police department.

Despite repeated calls to Keller Williams’ offices, Murphy has been unsuccessful in figuring out who wrote the note and mailed the package.

“We haven’t gotten anything,” said Det. Murphy. “No one has gotten back to me on the wallet. Unless I can say who found it, I can’t use the evidence in court.”

In early August, the Berkeley Police Department put up a picture of the wallet and note on its new “Who Are These Suspects?” website. Police have been posting pictures of suspected shoplifters, recovered stolen property, and other police incidents on the site for the past six months in an attempt to solicit the public’s help in solving crimes.

Mirabdal’s wallet was stolen on October 15, 2006. Police got a call around 10 pm that a man had been hurt on Poppy Lane in the Berkeley Hills.

When police arrived, they found Mirabdal, 19, barely alive. He had been stabbed more than 25 times in his neck and chest area.

A fingerprint found in Mirabdal’s car led police to Nicolas Flatbush, who was living on Parker Street in Berkeley at the time. Flatbush told police that he and a friend, Blake Mastro, had lured Mirabdal out in the car on the pretense of selling him some guns, according to court records. They intended to rob Mirabdal, said Flatbush. Flatbush told police he was the “muscle” in the operation and had been instructed by Mastro to sit behind the driver’s seat and pin Mirabdal down when Mastro mentioned the words “World Series”, according to court records.

But Flatbush was completely surprised, he said, when Mastro pulled out a knife and started stabbing Mirabdal while shouting out “So you hate Jews? So you hate Jews?

Mirabdal is of Persian descent and his family is Muslim.

After the stabbing, Mastro took papers and things from Mirabdal’s car, according to Flatbush’s statement to police.

Alameda County prosecutors apparently did not believe Flatbush’s account as they charged both him and Mastro with attempted murder and robbery. Prosecutors also added on an enhancement charge of grave bodily injury, which can add years onto a sentence.

But if Mirabdal’s wallet was found in North Berkeley, it may corroborate Flatbush’s story, since the wallet went missing from Mirabdal’s car that night, according to Det. Murphy.

Flatbush is free on $150,000 bail but Mastro has been held in jail without bail for more than three years.

The last four years have been extremely difficult for Mirabdal and his family, who live in Moraga.

The assailant punctured Mirabdal’s heart, sending blood throughout his body. His injuries triggered a massive stroke, and Mirabdal spent weeks in a coma. Doctors did not expect him to survive.

Mirabdal did not die, but remains incapacitated, according to his father. Once a strapping football player at Moraga High School, the 24-year old no longer has use of his hands and cannot feed or dress himself. His nerves were severed in the assault and he suffers from excruciating nerve pain.

Despite his injuries, Mirabdal is a student at Diablo Valley College.

His father, Ali Mirabdal, runs a copy shop on Shattuck Avenue in North Berkeley. He said the assault has profoundly transformed his life. Mr. Mirabdal, who fled Iran when he was 17 because he disagreed with the country’s political direction, said the attack has made him less trusting.

“My whole family has been shattered by this,” said Mr. Mirabdal. “There is not a day I don’t break down and cry three or four times.”

Mr. Mirabdal thinks Flatbush and Mastro did not want to just rob his son, but kill him. He considers the assault a hate crime.

“They did it to him because they thought he was a Muslim,” he said.

If anyone has any information on the wallet, please email Sgt. Murphy at ejmurphy@ci.Berkeley.ca.us or call the Homicide Detail (510) 981-5741.