The forensic examination of the crime scene was also due due to be continued with police technicians scouring the area for clues.
“Some of it will be completed today but it will continue for another couple of days,” said Tommy Nyman, a spokesperson for the police in Västra Götaland.
A formal remand request must be submitted by Tuesday at the latest.
Two men are suspected of murder and a woman is accused of harbouring a criminal.
Lisa Holm, who was named by police on Tuesday, was last seen at a café in Blomberg near Lidköping at around 6.30pm on Sunday after working a shift there.
Lidköping is a small town in a rural area north east of Gothenburg, and is close to two of Sweden's largest lakes. It is around 50km from the teenager's home town, Skövde.
More than 7,000 people disappear in Sweden every year, according to Missing People, but the search for Lisa Holm is one of the biggest in recent years and captured high media attention.
Around 900 volunteers joined the search for the teenager, searching woodland, fields and buildings in the region.