It was not unusual for Sean Suiter to be roaming through one of the city's most violent neighborhoods as night fell.

The 18-year police veteran spent his early days as an officer patrolling West Baltimore, returning often as a homicide detective seeking closure for those mourning loved ones lost on its streets.

Looking for answers is what Suiter was doing Wednesday while investigating the triple shooting of three young men left to die last December in a boarded-up house.

Suiter was working the case with his partner from the homicide unit and wanted to speak to a suspicious-looking man in a vacant lot between rowhomes. But shortly after Suiter approached, the man pulled a gun and fired.

With a single gunshot to Suiter’s head, the gunman transformed a detective charged with solving Baltimore’s murders into the city’s 309th homicide of the year.

Baltimore Police Detective Sean Suiter was fatally shot while investigating a triple homicide. (Baltimore Police)

The slaying of the father of five became yet another tragic symbol of violence in this crime-battered city, where the killings continue to soar and the mayor says crime is “out of control.”

“I pray for Baltimore,” said Dana Bell, the mother of one of the victims in the triple homicide Suiter was investigating. “If people don’t respect the law and life, they aren’t going to respect anything.”

As of Thursday night, law enforcement officials said they were actively searching for the gunman, whom Police Commissioner Kevin Davis called a “heartless, ruthless, soulless killer.”

“We remain dedicated and committed to finding the person who ended such a beautiful life of such a wonderful detective, husband, father and friend,” Davis said. “We will find the person responsible for this ridiculous, absurd, unnecessary loss of life.”

Suiter, 43, was a U.S. Navy veteran who had grown up in Washington, D.C., and lived with his wife and family in Pennsylvania. Suiter’s relatives could not immediately be reached.

Suiter was transported Wednesday to the R. Adams Cowley Shock Trauma Center shortly after the shooting at about 5 p.m., where he remained on life support until he was pronounced dead at noon Thursday.

Police cadets arrived to canvass the neighborhood near the scene of the fatal shooting of a Baltimore homicide detective. (Peter Hermann/TWP)

Police had only a vague description of the suspect, saying he is a black man who wore a black jacket with a white stripe and may be injured. The reward for information leading to an arrest and conviction in the case was increased Thursday to $169,000 after Maryland Gov. Larry Hogan (R) had the state boost the amount by $100,000.

Though Davis said, “it shouldn’t take 69 cents” for someone to “do the right thing.”

After the shooting, tactical units and helicopters fanned out in the area, with the neighborhood still taped off well into Thursday as police cadets went canvassing door-to-door.

It is the second time this month that a police officer has been shot in Baltimore. On Nov. 4, an off-duty D.C. police sergeant was fatally shot while sitting with a woman in a car in Northwest Baltimore. The case also remains under investigation with no publicly named suspect.

Crime has long been entwined with Baltimore’s identity, but the violence took on a renewed urgency when homicide rates reached historic record levels after Freddie Gray died in police custody in April 2015. Residents rioted and protested in the wake of Gray’s death, and already fragile relations between police and the community further deteriorated.

Before Wednesday, Baltimore had logged 308 homicides for the year, up 14 percent from 271 this same time in 2016.

In April, the 22-year-old son of a Baltimore police officer who was fatally shot during a 2007 attempted robbery also died by gunfire.

Months later, the brother of Baltimore police spokesman T.J. Smith was killed in his own apartment.

And weeks after that, a 97-year-old vet was bludgeoned to death in his pajamas during a break-in.

A prominent Baltimore defense attorney, a state delegate and a city councilman also count themselves among the grieving families who’ve had a relative killed this year.

“I’m sick and tired of being sick and tired of crime in the city of Baltimore,” City Council President Bernard C. “Jack” Young said.

Suiter was shot in one of the most dangerous pockets of Baltimore, which has one of the county’s highest per capita murder rates.

Johnny Felder, 41, who lives on Fremont Avenue, said he was at work when his wife called him about the Wednesday shooting two blocks from their home. Mayor Catherine Pugh is right in saying that crime is “out of control,” Felder said.

“We hear gunshots all the time down that way,” he said, pointing south to Fremont Avenue and Bennett Place, where the detective was shot.

Felder added: “I blame all sides. I blame the youth. I blame the parents. I blame the schools.” Felder did not mention the police on his list, and he said that was intentional. “I feel for them. I can’t imagine being in their shoes.”

Those who knew Suiter described the detective as a dedicated officer, who was respected by both residents and colleagues.

Bell, the mother of one of the triple homicide victims, said she talked to Suiter every week and that he had recently told her he had developed promising leads.

Suiter had told her, she said, that the gunman was targeting someone else and that her son, Antonio Davis, was caught “in the wrong place at the wrong time.”

“He was my rock,” Bell said of Suiter through sobs, shortly after learning he had died. “He always took my calls. I had no one to help me through this and he was it. He held my hand all the way. He promised me he would find my son’s killer. I don’t know what I’ll do without him.”

Bui and Hedgpeth reported from Washington. Clarence Williams and Jennifer Jenkins contributed to this report.