India, Nov. 14 -- Federal and local investigators probing the deadly shooting rampage in Washington, D.C.'s Logan Circle neighbourhood have uncovered chilling new details, revealing that emergency physician and gunman Dr. Matt Lambert directly confessed to a building manager over the phone while the attack was underway.

Charelle Ferguson, a building manager at the Metropole condominium complex where the violence erupted, told reporters that she received a phone call from Lambert shortly after initial gunfire broke out on Thursday morning.

According to Ferguson, she had contacted residents to check on their safety when Lambert answered and launched into vehement complaints regarding chronic water damage and toxic mould in his seventh-flo...