Washington ? Prosecutors say it was one of Sen. Ted Stevens’ friends whose secret, interest-free loan allowed him to make a killing in a Florida condominium investment six years ago. But they only identify the friend as “Person C” in a court filing on Thursday, and that the person was a partner in the company that built the condos.

Who is Person C? The identity couldn’t be determined for sure. But the developer of the project is the son of a lifelong Stevens friend. The late George Dewey Reycraft, who died in 2004, was Stevens’ roommate when they attended Harvard Law School. Reycraft’s obituary described Stevens as his “best friend.”

Stevens, 84, was indicted last month on charges he failed to disclose more than $250,000 in gifts, mostly from the oil services company Veco Corp. and its former CEO, Bill Allen.

But court papers filed Thursday also show that prosecutors hope to introduce evidence at his Sept. 24 trial that Stevens hid a $31,000 loan from a friend and then parlayed it into $129,250 in real estate gains.

The information about the real estate deal doesn’t represent a new charge against Stevens.

However, prosecutors said that they hope to introduce information about the real estate deal, as well as several other new assertions not contained in the original charges.

Stevens’ involvement in the Florida condo deal dates to 1999, according to his Senate financial disclosure forms. The 1999 form lists a $1,000 to $15,000 investment with the commercial lender, Pointe Bank, in Aventura, Fla. The investment was in Harbor Manor Development Ltd., doing business as Carroll Walk Ltd., a condominium development, according to the disclosure form.

Several South Florida business publications paid special attention to the Carroll Walk proposal, because it was the first high-rise to be built in Bay Harbor Islands in 30 years.

In an interview in Anchorage, Alaska, Friday, Stevens would neither confirm nor deny that Reycraft loaned him the money for the condo down payment, saying only “that’s what lawyers are hired for” and “I cannot talk about the details of that.”