Authorities arrested four people as part of an investigation into the deaths of two Frenchwomen in northwestern Argentina, the judge working the case said. Judge Martin Perez told AFP that those detained included three men and a woman, and they are due to testify on Monday. He declined to provide further details. A source close to the investigation said the people arrested were "all young," and included the daughter of a retired police officer and a police cadet, but declined to provide their names or ages. During an early morning raid, police found a camera and the cellphones of French university students Houria Moumni, 24, and Cassandre Bouvier, 29, whose bodies were found last week on a trail in an area overlooking the provincial capital of Salta. "The camera had pictures of them," the source added, noting that testimony from a rental car driver who was the last person to see the women had led to the arrests. On Tuesday, bricklayer Daniel Vilte was arrested for his links to the purchase or sale of the .22 caliber weapon used in the murder, though it has not yet been found. Two witnesses have told investigators they heard gunshots on July 16 in the part of the nature preserve where the bodies were found. One of the women was shot in the head and apparently sexually abused. The other was shot in the back. Investigators have taken DNA evidence from the bodies, including hair samples thought to be of the culprit and traces of semen from the victim who was said to have been sexually abused. Sources close to the investigation said they expected to determine the exact time of death in 10 days, data considered key to determining whether they were held captive before being killed. The women had arrived at the nature preserve on July 15 and their bodies were found two weeks later. Their bodies have been flown to Buenos Aires where they await repatriation to France.