STEVENSVILLE, Md. (WJZ)—A former cop is caught on the wrong side of the law. The former Baltimore City police officer is accused of killing his neighbor in Queen Anne’s County.

Weijia Jiang tells us the problems all apparently started with a fight over a dog.

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Police say that fight killed a man– known as a devoted husband and father of two– by a man who has been in and out of court several times over many neighborhood disputes with others.

In the exclusive neighborhood on the Eastern Shore, friends and family members are mourning the death of 55-year-old Mark Xander.

Police say his next-door neighbor, former Baltimore City police officer Charles Richter, shot him in the back Sunday evening.

“It’s the worst thing that’s ever happened to our family. It’s a nightmare. We’re numb,” said Steve Xander, victim’s brother.

Investigators believe Xander’s dog went on Richter’s property, sparking an argument.

Deputies found Xander’s body in his own front yard with his Rottweiler by his side.

“That’s a factor we’ll consider as potential motive. But with any investigation, we approach it objectively,” said Lance Richardson, Queen Anne’s County State’s Attorney.

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Court records reveal Richter filed multiple charges against neighbors for noise complaints and trespassing. Those that live there describe him as confrontational.

“He’s sued just about everyone on this street. He’s dug everybody on this street into court, including me. A couple of people moved because of him,” said Jospeh Saia.

WJZ found videos Richter posted of himself on YouTube. The 66-year-old was on the Baltimore police force from 1965 to 1978. He ran for county sheriff twice, losing both times.

“He was considered a loose cannon by everybody,” Saia said.

Now Richter faces many charges, including first-degree murder.

“I just hope that nothing slips through the cracks, and some crazy thing will let this maniac off,” said Steve Xander.

After the shooting, Richter was taken to the hospital complaining of chest pains. A couple of hours ago he was transferred to the county detention center.

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Richter will have a bail review Wednesday morning.