US prosecutors charge two sons of former President Ricardo Martinelli after they were arrested in Guatemala on Monday.
Panamanian authorities on Saturday were investigating the murder of seven young people near a lake about 80 km (50 miles) north of the capital, a prosecutor said.
The bodies of the victims, four women and three men ranging in age from 17 to 22 years old, were found on Saturday, homicide prosecutor Adolfo Pineda told reporters.
Some people in the group managed to escape the attack and are assisting authorities with the investigation, Pineda added.
Some of the dead had injuries consistent with gunshot wounds, but the cause of death has yet to be determined, Pineda said. The motive for the attack is also under investigation.
“It really is a shocking occurrence from all points of view,” Pineda said.
Local media reported that some of the victims’ family members had reported them missing on Friday. The group had gone out to swim, according to local media.
The attack took place near Gatun Lake, a scenic man-made lake that forms an important part of the Panama Canal.