Paul Pierce/espn

A man once accused of stabbing Boston Celtics star Paul Pierce was sentenced Thursday in Boston federal court to 30 years in prison for attempting to kill a DEA informant, the U.S. Attorney’s Office said.

Trevor A. Watson, 44, of Boston, was found guilty in December in U.S. District Court in Boston of stabbing the informant 10 times outside of Ann’s Unisex Barbershop on Tremont Street on the south end of Boston on Feb. 27,  2010, the U.S. Attorney’s Office said.

Evidence in court showed Watson stabbed the informant, who survived the attack after emergency surgery to repair his damaged colon and intestine.

Authorities said while stabbing the informant, Watson said: “You talking, huh? you telling.”

During trial, evidence surfaced that WATSON was charged with the attempted murder of Boston Celtic Paul Pierce in 2002. However, the jury acquitted him after multiple eyewitnesses changed their testimony, authorities said.

The U.S. Attorney’s Office said Watson tried to get witnesses in the DEA case, including the informant, to change their statement to authorities.

He wrote letters and made phone calls from prison in which he wrote: “I had introduced my lawyer to the fact that if the victim in my case was to sign an affidavit saying I’m not the guy who stabbed him, it was some Spanish guy about 30, which I am not either, I’ll be alright …” and “The Paul Pierce case was the same way, but at trial he changed his statements and I got found not guilty of att. mur. (attempted murder).”

Read Government’s Sentencing Memorandum