An 18-year-old man who was arrested Friday after a ringing cell phone led to the detention of four teenagers (story here) in an elaborate robbery called today to say that he was not involved in the primary crime.

The man, whose name was not used in the story and will not be used here, said today that he has been charged with a felony count of  possessing a deadly weapon, but said that he was not involved in the robbery, and that the weapon was planted on his person.

 ”One of the other guys stuck it in my backpack,” the man said.

The man was arrested along with three friends, ages 16, 16 and 14, Friday at Central Park after a San Jose man was pummeled nearby by a group of attackers whom police say conspired to sell him a PlayStation3 over the Internet.

Police said the boys wandered away from the park  — where their charter school was meeting during the daytime — and told the San Jose man to meet them at a nearby home.

When the victim arrived, one of the teens told him that the gaming system was inside the house and that it could be tested. The victim then walked toward the home and was jumped from behind.

Minutes later police were summoned to the park, where the teens fled, and arrested the boys. The three juveniles were arrested for the robbery and assault, while the 18-year-old was jailed only for possessing the weapon.

According to the 18-year-old, he was at the park the entire time and not involved in the robbery.

“I didn’t even know what was going on,” he said.

He saw his friends run back to the park, and they then passed the collapsible baton around, ultimately sticking it in the 18-year old’s back pack, he said.

On Friday, Detective Bill Veteran said that officers watched the teens pass the baton several times before apprehending them.