Prince George's County police are investigating whether the men responsible for a deadly robbery rampage early Monday morning might be connected to more than a dozen similar stickups in Washington.

Detectives are searching for four men who they believe committed the rash of violent crimes that spanned two miles of Prince George's and ended with two men dead and two others robbed.

Construction worker Herminio Moscoso, 26, was shot and killed at 5 a.m. in Glenarden as he warmed up his van to take himself and his two younger brothers to work. About 15 minutes later, auto mechanic William Everette Miller, 46, was fatally shot in a botched robbery in Landover.

Shortly after, two other men were robbed in separate incidents, one at a Fairmount Heights gas station, as the assailants worked their way south along Martin Luther King Jr. Highway toward the District, according to police.

County detectives are working with D.C. police, who are investigating 16 robberies and attempted holdups at gas stations in the District since June 1. Investigators believe those crimes are being committed by at least two groups of gunmen.

The robberies have occurred in Northeast and Southeast Washington, and several closely resemble the robberies and carjackings that occurred Monday in Prince George's, police said.

D.C. police Lt. Pamela Burkett-Jones said investigators were discussing the robberies with Prince George's authorities to see whether the cases are connected.

"We're sharing information," Burkett-Jones said. "We're comparing notes."

Maj. Vincent Gay, commander of the Prince George's Criminal Investigations Division, said the two agencies are developing leads to "see if any of the aspects are connected."

Gay said there has been a spike of robberies in the county, but he has not noticed a specific increase at gas stations.

Thirteen of the robberies in the District occurred between 4 a.m. and 9 a.m., and many of the victims were on their way to work when the holdups occurred -- a fact that worries police because motorists might not be paying attention to their surroundings at such hours, Burkett-Jones said.

As many as four assailants -- two of whom were armed -- have participated in some of the holdups.

The robbers "are dangerous; they are toting guns," said Burkett-Jones, who added that the victims didn't realize they were being robbed until the gunmen demanded cash. "It all catches them by surprise."

Police began tracking the robberies June 22, when four men carjacked a green Ford Expedition from a woman pumping gas at a Chevron station about 5:30 a.m. in the 3000 block of Martin Luther King Jr. Avenue SE.

The 50-year-old District woman had just gotten back into her vehicle when a man prevented her from closing the door and pulled out a gun, police said. She got out, and the man drove her car away, police said.

Another man was seen standing near a Crown Victoria, which then followed the Expedition out of the service station, police said.

In the next hour, using the stolen Expedition as their getaway vehicle, the robbers held up patrons at two other gas stations -- in the 2500 and the 3300 blocks of Benning Road NE, Burkett-Jones said.

The gunmen then drove into Prince George's, where they committed another robbery, Burkett-Jones said. Further details were not available.

Two weeks later, two robbers held up patrons at three gas stations in the District. Police do not believe the July 5 robberies were committed by the same people who orchestrated the June 22 holdups because witnesses described different assailants.

Herminio Moscoso, with children Andrea, left, and Michele, was shot and killed as he warmed up his van to go to work Monday morning.