A D.C. Council campaign worker charged with killing a neighbor in a dispute over a dog has a history of run-ins at city hall, including for threatening to "go Southeast" on an aide, records show.

At his arraignment on Monday, 56-year-old Ellsworth Colbert pleaded not guilty to a charge of second-degree murder in the fatal stabbing of his 37-year-old neighbor Robert L. Wright. Colbert was held without bond.

According to charging documents, Wright was walking a dog near Colbert's home in the 3500 block of Pope Street SE around 10 a.m. Sunday.

Colbert emerged from his home and confronted his neighbor about the dog getting near his yard, police said. Neighborhood listservs said Colbert was angry over dogs defecating in his yard.

Colbert pulled out a knife and cut Wright, who then grabbed a shovel, police said. Colbert tackled him to the ground. After a short tussle, both men got up and walked away.

But Wright fell to the ground with several stab wounds to his body, police said.

Records show that Colbert has long battled city hall, most recently over a job he lost 15 years ago.

Twice Colbert has been barred from the District building.

On Jan. 21, 2011, Colbert threatened a staff member of D.C. Council Chairman Kwame Brown.

"Don't make me go Southeast on you," Colbert said, according to court documents.

Colbert was charged with threatening to injure a person.

He had previously been barred from the Wilson Building on July 10, 2009, although the details of that banning were not included in the charging document.

In 2006, Colbert was arrested after he allegedly stabbed a man with a ski pole during a traffic encounter. Those charges were dropped.

Colbert is a volunteer in the campaign of D.C. Council Ward 7 challenger Kevin B. Chavous, the candidate who himself was arrested in December on a charge of soliciting a prostitute.

"I hope that the allegations of Mr. Colbert's involvement in this killing are false," Chavous said in a news release.

As first reported by the Washington Post, Colbert testified last week before a city council oversight hearing for the Office of Employee Appeals.

Colbert testified that he was unfairly fired from a city job in 1997 after he "whipped" his boss in a fist-fight.

Colbert said that he has been unemployed since, and he deserves his job back.

"I guess they thought I was going to die ... but I ain't. I've been here 56 years. I'm Southeast born, I'm Southeast bred, and when I die, I'll be Southeast dead."