The D.C. Corrections Department continued its investigation yesterday to determine how pieces of mice got into some food served to inmates of the D.C. jail.

Several inmates set a small fire in their cellblock after they discovered the foreign matter in their food Sunday, corrections' officials reported. The blaze, started by setting fire to a piece of newspaper, was fueled by bed linen and similar items, but was quickly extinguished by guards. The city fire department was not summoned.

Corrections spokesman Leroy Anderson said the fire was set at about 5:45 a.m., shortly after breakfast had been served. The incident occurred in Cellblock South 1, a section for inmates who are separated from the general jail population for various reasons, including histories of violent behavior.

About 100 inmates were in the cellblock at the time and were evacuated briefly to a recreation area until smoke had dissipated.

There were no injuries, and Anderson said no disciplinary action had been taken so far against the inmates who set the fire.

"The scrapple the item involved was delivered to us frozen and then heated," Anderson said. "The mouse parts were not cooked, so we can only conclude that they were placed there after the food was heated."