An abducted 15-year-old girl in Minnesota managed to flee this week, following a month of sexual and physical abuse in captivity, in part by swimming across a lake to safety.

The teen was last seen Aug. 8 at her home in Alexandria before investigators believe she was approached outside by a man with whom she was acquainted.

Watch: Duo Arrested After Livestreaming Alleged Kidnapping on Facebook

Cops say the man, since identified as 32-year-old Thomas Barker, asked the teen for help with something, which prompted her to get into his vehicle.

Police say Barker drove the girl to his home, where he allegedly restrained her with zip ties, repeatedly assaulted her and threatened her with weapons.

A second suspect, who police have identified as Barker's 31-year-old roommate Joshua Holby, allegedly also took part in the assaults.

The third suspect, Steven Powers, 20, arrived at the home about two weeks after the abduction and allegedly also participated in the assaults, which cops say continued over the 29 days the girl was held.

For those four weeks, a broad and intense search for the girl continued unabated in the area and a reward for information in the case climbed to $7,000.

In the end, it was the teen's own daring and will that led to her safe return.

The wheels for her return were first put in motion late last week when cops say the suspects took the girl from the house to various locations including a cornfield and a foreclosed property in Grant County.

Then, on Tuesday afternoon, cops say the three men left the girl alone for the first time in 29 days while they traveled to a nearby town for lunch.

She took the opportunity and ran for help, knocking on doors at several homes and eventually swimming across part of Thompson Lake, a 45-acre body of water in Douglas County.

Back on land, the girl located a home where the resident who recognized her from news stories about her disappearance and called 911.

Read: H&M Security Guard Accused of Using Position to Kidnap or Rape at Least 3 Women: Cops

The teen helped identify the three men, who've since been arrested and are being held on probable cause kidnapping, false imprisonment and assault.

Specific charges will be determined by the Douglas County Attorney, officials said.

Watch: Missing 4-Year-Old Found After Man 5,000 Miles Away Uses Pizza to Lure Kidnapper