EVERYONE HAS that friend or co-worker, the eternally grateful person who's just happy to be alive - and can make you feel the same way by their sheer proximity.

For first responders in eastern Delaware County, that guy was 26-year-old Mark Hudson, a part-time police officer in Darby Borough for the past four years and a volunteer firefighter in Yeadon since he was a teenager.

In fact, Hudson said as much on his Facebook page just two months ago.

"Everyday above ground is a great day," Hudson wrote in a January status update that made its way around the Internet again yesterday.

Hudson died Saturday of a gunshot wound to his chest that he suffered while inside his well-kept rowhouse on Magnolia Avenue in Darby Township. His 27-year-old girlfriend - who had allegedly threatened him before - was inside at the time of the shooting, about 4:30 p.m., and was taken away in handcuffs, according to neighbors.

No charges in connection with his death had been filed as of last night.

"This absolutely is not a suicide," said Darby Borough Police Chief Robert Smythe. "He absolutely did not take his own life."

Smythe said last night that investigators were continuing to question Hudson's girlfriend. The shot that killed Hudson was fired from his service weapon, he said.

Yeadon Fire Chief Michael Diienno said Hudson joined the firehouse when he was a shy 16-year-old, and his mother was worried about him hanging out with the wrong crowd.

"The firehouse gave him some direction," Diienno said.

Diienno said Hudson had served as lieutenant for a few years, helping to train the younger firefighters. He stayed on as a volunteer firefighter after he took the part-time police position in Darby Borough.

"There have been a lot of times where he was working day work in a police car and we'd get a fire call at night, and he would be here," Diienno said, adding that Hudson could instantly change the atmosphere in a room with his infectious smile.

Neighbors say police had been called to Hudson's house numerous times for apparent domestic disputes.

"They put on a happy face, but you don't know what goes on behind closed doors," said neighbor Kim Martin.

But, she said, Hudson and his girlfriend were both friendly neighbors.

"We felt safe. It's nice to have a cop on your street," Martin said.

Diienno said Hudson's girlfriend may have been the aggressor in the relationship. He said Hudson had told him a few months ago that he was having problems with her and had gone to the authorities seeking help.

"He had filed some paperwork," Diienno said. "But I never thought they had issues that would amount to this."

"It's a shame what happened to him," neighbor Tom Robb said of Hudson, whose pickup truck was still parked around the corner yesterday. "God bless him."

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