The U.S. Army private's lawyers rested their case in Fort Meade, Md., after questioning the two witnesses who said officers working with classified information listened to music, watched movies and played computer games, The Baltimore Sun reported.
Manning, an intelligence analyst deployed to Iraq, is accused of turning over hundreds of thousands of classified documents to the whistle-blowing Web site WikiLeaks. Among other things, Manning, 24, is charged with aiding the enemy and violating the Espionage Act.
Sgt. Daniel Padgett, who worked with Manning at a "sensitive compartmental information facility" in Iraq, said there was no clear chain of command.
"There could have been more oversight," Padgett said.
Capt. Barclay Keay, who oversaw Padgett and Manning, said he was surprised by the relaxed working environment.
"I thought it was kind of odd," Keay said.
Manning's lawyers have not seriously challenged the evidence showing Manning had access to classified documents and the ability to upload them to WikiLeaks, the Sun said. Instead, they've focused on his work environment and have stressed his struggle with gender identity.