ANNAPOLIS, Md. -- A man who had a long-running feud with an Annapolis newspaper blasted his way through its newsroom with a shotgun on Thursday, killing at least five people in one of the deadliest attacks recorded on a U.S. media outlet, authorities said.

The suspect, described as a white man in his 30s who lives in Maryland, fired through a glass door, looked for victims and then sprayed the newsroom of the Capital Gazette newspaper group in Annapolis with gunfire, police and a witness said.

Among the victims was Capital Gazette editor Rob Hiaasen, according the Baltimore Sun, which owns the newspaper group.

The suspect is Jarrod Ramos, 38, of Laurel, the Capital Gazette and Baltimore Sun reported citing law enforcement.

In 2012, Ramos brought a defamation lawsuit against Eric Hartley, formerly a staff writer and columnist with The Capital, and Thomas Marquardt, then editor and publisher of The Capital, according to a court filing.

In 2015, Maryland’s second-highest court upheld a ruling in favor of the Capital Gazette and a former reporter who were accused by Ramos of defamation, the Baltimore Sun reported.