* Freddie Mac CFO found hanging in basement -police source

* Freddie Mac: No indication death linked to federal probe

* Kellermann 16-year Freddie veteran, key in accounting

* Neighbors and co-workers shocked, saw no signs of stress

* Kellermann got $850,000 retention bonus in Sept (Adds details)

By Deborah Charles

RESTON, Va., April 22 (Reuters) - The finance chief of troubled U.S. mortgage giant Freddie Mac (FRE.P: Quote, Profile, Research) (FRE.N: Quote, Profile, Research), David Kellermann, was found dead on Wednesday after apparently committing suicide, a police source said.

Kellermann, promoted to acting chief financial officer last September after the government took control of the company, was found hanging in the basement of his home in an affluent Washington suburb at around 5 a.m. (0900 GMT).

There was no immediate indication what would have driven 41-year-old Kellermann, who was married and had a young daughter, to kill himself.