The 16-year-old son of a former Maryland labor leader was charged yesterday with Sunday night's stabbing deaths of three young girls who lived less than a block from his home in a middle-class subdivision in nothern Anne Arundel County.

The arrest of Stuart L. Kreiner - a teen-ager apprently shunned by many of his contemporaries as "straight arrow," "sissy" and "sort of weird" - came only a few hours after his father began to suspect his son might be involved in the crime, and called Anne Arundel County police.

A hunting knife and a jacket, both covered with what appeared to be bloodstains, were taken from the youth's home at 7973 Cross Creek Dr. yesterday, along with about 40 other items "of evidentiary value," Anne Arundel County police officials said yesterday.

The three girls, sisters Deborah Hogan, 10, and Theresa Hogan, 8, and their playmate, Ann Brzeszkiewicz, 8, were killed sometime between 7:30 and 9:30 Sunday night near a makeshift play fort in the woods, a few hundred yards from their homes. The Kreiners' split-level home, almost directly across Cross Creek Drive from the Brzeszkiewicz house, backs up onto these same woods.

Sources close to the police investigation said yesterday that Edward T. Kreiner, former executive secretary of the Maryland Classified Employees Association, which represents thousands of Maryland state employees, had called police after finding some objects in his home that led him to suspect his son.

Lt. Robert Russell, who led the police investigation, noted that Kreiner and his wife allowed police to remove material from the house without requesting a search warrant. The family "has been extremely cooperative throughout the investigation," said Acting Police Chief George W. Wellham.

Stuart, the murder suspect, is the second of the Kreiners' three children and a choirboy at the local Presbyterian church. The slight, bespectacled youth avoided drugs, alcohol and cigarettes and had never been in trouble with police, according to neighbors and police officials.

But these same model-child qualities apparently rubbed many of the youth's schoolmates the wrong way. One 17-year-old neighbor, who asked not to be identified, said Kreiner was a "sort of outcast" in the neighborhood because he was "too straight" and "no one liked that kind of person."

"He really didn't have too many friends," recalled Micahel Szubinski, 17, who had been a classmate of Kreiner's last year when both were sophomores at the Old Mill High School near their Southgate neighborhood in Glen Burnie.

"He was having a lot of trouble" at the school, Szubinski said, "people called him a sissy." Kreiner transferred over the summer to a nearby private Catholic high school, Martin Spaulding.

Other neighbors said that Edward Kreiner had wanted his son "to have some religious instruction in his education." Stuart started at Martin Spaulding last month.

Because of his rejection by his peers, some neighbors said, Stuart Kreiner often played with neighborhood children a few years younger than himself."He told me the big kids played too rough," said one child who asked not to be identified.

The three girls had left the Brzeskiewicz home shortly after seven Sunday evening, and were last seen on a footbridge leading into the woods where children often play.

Their parents called the police and reported them missing after looking around the neighborhood for a couple of hours after dinnertime. An all-night search by police, neighbors, and a bloodhound, finally turned up the girls' bodies at about 8:15 the next morning.

The three were found lying face down in a shallow, muddy stream that runs directly beside a play fort, made of plywood boards propped up against a tree. Pools of blood were discovered near the fort itself.

Two of the girls had been stabbed more than 30 times, according to police, and the third had been stabbed at least a dozen times in the back. Police characterized the blows as extremely forceful.

The woods behind the 15-year-old subdivision has for years served as a magnet for neighborhood children, who had dug out or built up perhaps half a dozen different "forts." They would roam the network of small trails and broad dirt tracks on bicycles, minibikes and small motorcycles.

"Kids have played down there for years," a neighbor John Holihan said on Monday. "There are several places back there where they put things together and call them forts."

Holihan's own 10-year-old daughter, Debbi, had been with the three murdered girls until about 6 Sunday night, and had once tried to get down to the woods with them that afternoon. But the foursome had turned back, finding that the trails, soaked by a daylong rain, were impassable.

The funeral for the three girls is scheduled for 10 a.m. today at Holy Trinity Catholic Church in Glen Burnie. Half an hour earlier, Kreiner is scheduled to be arraigned on three counts of first-degree murder at the county District Court in Harundale.

Lt. Russell said the police still have no real clue as to the motive for the slayings. "We have nothing," he said. "No torture, no beating, nothing other than they were stabbed to death.

"The father of the suspect, I think, is crushed," Russell added. 'He doesn't have any idea why" his son might be included in something like this.

On Monday morning, a few hours after the discovery of the bodies, when the normally placid neighborhood was crowded with police cars, reporters and television cameras, Edward Kreiner stood outside his home, shaking his head at the news.

Kreiner, who until this past summer had been head of the state employees organization, was acquainted with many of the reporters on the scene and invited several of them into his house to use his telephone, offering them fresh coffee, while his wife busied herself making meatballs, deviled eggs, and carrot salad to take to the Brzeskiewicz family.

"You feel scared," he said, when asked about the murders on Monday. "You feel sick to your stomach. I've got a 9-year-old daughter. What about her/" He added that his daughter was not allowed to play in the wooded area.

The Kreiner family left home sometime before the arrest was announced yesterday, and was not available for any comment.

Stuart Kreiner's arrest ended an intensive three-day investigation that had focused on the Southgate community, a neighborhood of about 400 homes located 12 miles south of Baltimore.

From the time the bodies were discovered, between 50 and 60 county police officers had inched through the woods looking for clues, had followed up dozens of tips telephoned in by members of the community, and had searched through the garbage cans of every home.

Tuesday night, two policemen had even slept out in the fort, which was 10 or 15 feet from the spot where the girls' bodies were found. They hoped, according to police Sgt. William Chaplin, that the killer might return to the scene.

Early in the investigation, on Monday night, Kreiner was "one of at least 100 people we had as suspects," Lt. Russell said yesterday. But then "we really focused in on him last (Tuesday) night."

Russell said that the detectives had not interviewed the youth during their search but "they talked to people about him."

In contrast to the words of nearly every neighborhood teen-ager interviewed Russell said that young Kreiner was "the kind of boy that I understood kids knew him and liked him.Kids would bring their bikes to him and he'd fix them. All indications are he's a hell of a nice kid."

The families of the dead children, according to Sgt. Chalin, expressed "relief, and sorrow for the boy's family." And Father Joseph Connolly, the pastor of St. Bernadette's Catholic parish, of which both the Hogan and the Brzeszkiewicz families were members, said that Richard Hogan yesterday quietly said "They (the Kreiners) are going to need a lot of help."

Neighbors of both victims' and the suspect's families felt similar, conflicting emotions, June Wilkes, a next-door neighbor of the Kreiners, said yesterday that "I'm fixing dinner for the Brzeszkiewiczes and right now my heart is also bleeding for the Kreiners."

June and Robert Wilkes and other neighbors remembered Stuart Kreiner as a "quiet individual" who, except for a fling in Little League baseball, had few interests outside his school work.

"He'd ride his bike in the woods or go down there and collect firewood," said Ron Brylla, another former classmate at Old Mill High School. And Michael Szubinski added that "he never really did anything."

At the Spaulding school, 15-year-old Lauri Marquis recalled, Stuart "really got good grades." Marquis added, that she had lived in the same neighborhood as Stuart for 11 years but "no one really knew him well."

Officials of the Spaulding school refused all comment on the case yesterday, and asked reporters to leave the school grounds.

The whole case, Anne Arundel County Police Chief Ashley Vick said yesterday, was "the saddest I've ever witnessed in 22 years as a police officer. There are just no winners in this case."