( CNN ) -- A quarrel between occupants of two vehicles at a McDonald 's restaurant drive-through in southern Finland erupted in gunfire Tuesday , leaving three men dead , police said . Three occupants in one of the vehicles have been arrested , said Peter Fagerholm , a detective inspector in the town of Porvoo . The two vehicles were in line at the restaurant about 2 a.m. when the quarrel began , Fagerholm said . Shots from a semiautomatic handgun were fired from a Toyota SUV into a convertible driven by a pregnant woman and carrying four men . Two of the men in the convertible , ages 28 and 45 , died at the scene . Another 28-year-old man died Tuesday afternoon at a hospital in Finland 's capital , Helsinki , about 50 miles to the west , Fagerholm said . Two of the men were shot in the head , the other in the chest , he said . The cause of the argument was not immediately known . `` We believe it was a very small issue '' that escalated , Fagerholm said late Tuesday . He said he does n't believe the parties in the different cars knew each other , or that the shooting was preplanned . The SUV carried one woman and two men , Fagerholm said . One of the men , 41 , is the principal suspect . In 1995 he was sentenced to life in prison on one count of murder and two counts of attempted homicide , Fagerholm said . He was released on parole in December . Fagerholm would not release the suspect 's name . Authorities are speaking with witnesses in a third car in the drive-through line . CNN 's Lianne Turner and Phil Gast contributed to this report .
Three men were shot to death during a quarrel outside a restaurant in Finland . One of two vehicles at the McDonald 's drive-through was driven by a pregnant woman . The other vehicle had been involved in an accident and fled from police, but it is unclear if that car also belonged to the suspect or his accomplice.