PEORIA, Ill. — Videotapes presented at the sentencing hearing for an al-Qaida sleeper agent show long days spent alternately pacing and reclining on a concrete floor during the nearly six years he was held as an enemy combatant.

Lawyers for 44-year-old Ali al-Marri argued today that he was held under unusually tough conditions at a Navy brig in South Carolina. They contend that should be considered by a federal judge in Illinois who will sentence him.