It was a bloody start to the weekend in Miami-Dade County, with three separate shootings that left six men dead and a seventh critically injured by sun-up Saturday morning.

Miami-Dade homicide detectives investigated a deadly accident between friends, a drive-by shooting and a bitter argument that both sides lost between 5 p.m. Friday and 5 a.m. Saturday.

Investigators made one arrest: 18-year-old Anddy Entrena, charged with manslaughter in connection with the death of his best friend, Ivan Sanchez, 18, of Hialeah. Entrena was horsing around with a revolver, believing it wasn't loaded, when it went off about 5 p.m. Friday night, police said.

''I just don't understand,'' Sanchez's mother, Miriam Martinez, said Saturday evening. ''They were best friends. He slept in my house. I fed him.''

Friends of the two young men also said they were close, both avid skateboarders. Entrena is a new father. Sanchez had recently decided to go back to school to get his General Equivalency Degree.

''He kind of started life over again,'' said Sanchez's ex-girlfriend, Krystal Cardona. ''He realized that he needed to make some changes.''

A handful of friends gathered in Hialeah Saturday night to put together a collage of pictures they had of Sanchez that his parents could display at the funeral.

''I'm still in shock because you don't think this happens to a kid like Ivan, who's just a good kid, who's not in a gang or involved with drugs,'' his uncle, Carlos Sanchez, said.

Less than 12 hours later, at about 4:30 a.m. Saturday, two men shot and killed each other in the 186 block of Northwest 27th Avenue, Miami-Dade police said in a press release.

They didn't release the names of either man or any other details about the Miami Gardens shooting.

It was only about 30 minutes before Miami-Dade homicide detectives were responding to another shooting in northwestern Miami-Dade, this time in Liberty City.

Three died and a fourth man was hospitalized from that incident, near the intersection of Northwest 79th Street and 22nd Avenue, according to a press release from Miami-Dade police.

Police did not release the names of any of the victims.

All four men were in a silver Toyota Highlander traveling west on 79th Street, approaching 21st Avenue.

''An unknown vehicle pulled alongside the Highlander and fired multiple shots into it, striking all four occupants,'' the news release said.

The driver lost control, plowing across a parking lot and striking several trees.

Only a gnarled shell remained of the Highlander. The front bumper appeared to have been sheared off when the car rammed palm trees and a brick wall. By early Saturday afternoon, family members and friends of the victims gathered in the neighborhood.

A Miami-Dade Fire Rescue ambulance attended to a woman who bystanders identified as the mother of one of the victims. She became distraught after arriving near the scene of the shooting.

At the U-Gas station at the corner of 79th Street and 22nd Avenue, other family members broke down crying as the identities of the victims trickled through the grapevine.

One woman pounded her feet on the ground, wailing ''my boy.''

Al Hunter, 46, who identified himself as an Army veteran who had fought in Iraq and received a Purple Heart after being shot, said it was a sad day in the neighborhood.

''We rode down the street shooting at people, but that's different, that was a war,'' said Hunter, referring to his service in Iraq.

''This is a war, too, I guess.''