Search for the Brown University gunman resumes after person of interest released

Authorities continued their search for a gunman who attacked students at Brown University, killing two and wounding nine others (Leah Willingham/AP)

Police renewed their search for a gunman who killed two students and injured nine others a day after releasing a man they believed was a person of interest.

Authorities knocked on doors, searching for any video there might be of the Brown University gunman, who was seen in grainy footage walking away from the weekend attack.