Maryland State Police in Leonardtown said little at midweek about their investigation into the fatal weekend shooting of a 19-year-old Great Mills man, but the victim's family and friends said they believe his death stems from a long-festering rivalry between a group of Lexington Park-area youths and another in nearby Oakville.

Friends and relatives of Darryl R. Mackall said he was involved in a fight with longtime foes from the Oakville group on Saturday night while at the Callaway Club, an after-hours pool hall that does not serve alcohol. Several St. Mary's County residents said the Callaway establishment, known locally as Rick's, has been a hangout for rival groups of youths. Mackall left the club early Sunday morning, drove a friend home and was found just after 5 a.m. in his 1989 Buick Riviera, which had crashed into a telephone pole on the northbound side of Chancellors Run Road near Great Mills.

Doctors at St. Mary's Hospital, where Mackall was treated initially, transferred him to Washington Hospital Center because of the seriousness of his head injuries from the crash. At the Washington hospital, emergency physicians discovered a bullet wound in the teenager's head, according to a police report. He was pronounced dead about 1 p.m. Sunday.

This week, State Police investigators have brought in a special homicide unit, and St. Mary's County sheriff's officers have questioned students at Great Mills High School, where Mackall had been a standout basketball player and popular student before he graduated in May. On Tuesday, neither agency would directly address the existence of a rivalry among area youths that Mackall family members and others described.

"I can't say I haven't heard things," said St. Mary's County Sheriff Richard J. Voorhaar. "I've heard things over the years, but whether those things can be applied to this case, I can't say."

Maj. Thomas Bowers, commander of criminal enforcement for Maryland State Police, would not comment on the existence of any specific rivalry, but said homicide detectives are investigating "certain suspects."

"We haven't ruled anything out yet," Bowers said. "We've interviewed the family, and we haven't ruled out any information they or any other sources have provided us."

But local residents said they are all too familiar with the rivalry, which they say has grown more intense in recent years to include fights in parking lots and even gunshots fired anywhere the two groups come face to face--at an annual cabaret show, a local carnival, baseball games or a local hip-hop club. Mackall's mother said her son went to court after an incident in which a beer bottle was smashed over his head. Erica Bush, 19, recalled one occasion when she ran to her car dodging gunfire while pregnant with Mackall's son, Darryl Jr., now a year old.

Students and recent graduates of area high schools said the feud is legendary.

"It's been going on forever," a 20-year-old woman who was in Mackall's graduating class at Great Mills High said with a shrug. She also asked not to be identified by name. "They don't like us and we don't like them."

Mary Herbert, a 28-year-old Leonardtown High School graduate, remembers when the tension between youths from Oakville and those from Lexington Park or Great Mills was a less intense competition based on sports, clothes and cars. Now, she said, the groups have become more territorial, with calls of "Up the pike!" signaling the arrival of youths from Oakville.

"It's just changed," Herbert said, noting that the skating rink, arcade and youth-oriented clubs of her high school days have closed down in recent years. "The only thing they can do now is hang out. For a role model, you see your uncles in a fight [because of the rivalry]. It keeps going till it's out of control."

It appears that the only thing the factions agree on is just where Lexington Park territory ends and Oakville turf begins. The perceived dividing line is marked by a weather-beaten wood building on Route 247, Loveville Road, known simply as "The Shop." The building is more than 50 years old and is really Fenwick's Tavern, a bar and restaurant known for its fried chicken and pounding go-go music after games at the adjacent Oakville baseball park.

Glenn Fenwick's grandfather opened The Shop decades ago, he said on Tuesday afternoon as he and a couple of other men played pool in the dimly lit tavern while a set of drums--the backbone of go-go music--sat silent in a corner. Fenwick said his father, now the bar's owner, has instructed him to call the police any time fighting among the youths grows too violent. Fenwick lives in Washington, but said he is well aware of the feuding groups in his father's home town and recalls that as far back as 1989 Oakville kids chanted "Up the pike hustlers!" while a go-go band played.

"They have fights out in the yard," Fenwick said. "I stay away from it. I don't know names, I don't know anything. I just call the police."

A 26-year-old Oakville man who identified himself only as "Al" said this week that the discord between the groups hasn't evolved from any specific incident, but is a building jealousy over material items and high school sports.

"It's always been like that," he said. "When you hang with somebody and grow up with them all your life, you protect them. That's what happens. But it's getting blown out of hand."

While no one had been charged in the case by midweek, thus leaving any connection to the ongoing youth rivalry unconfirmed, some residents already worried about a backlash from Mackall's killing. Several Lexington Park and Great Mills residents said they will not attend this weekend's baseball banquet--an annual event after the local league's season ends--for fear of a showdown between the two groups.

"Kids at school are talking about retaliation," said Great Mills High senior Salina White, 17, who did not know Mackall. "I hope it'll stop, but it's not going to. But you can hope."

Staff writer Annie Gowen contributed to this report.

CAPTION: DARRYL R. MACKALL. . . played Great Mills basketball