Courtesy Photo Abby Hill is pictured in an undated photo.

ALPENA — What began in early August as a search for a missing teenager has since expanded into two homicide investigations and an alleged armed hijacking.

Here’s what we know so far:

CHARGES POSSIBLE

Police this fall found the bodies of two women — Brynn Bills, 17, and Abby Hill, 31 — in separate searches in Alpena Township.

Separately, Muszynski charged two men — Brad Srebnik, 35, and Joshua Wirgau, 34 — with multiple crimes over an alleged armed hijacking of a tow truck driver this fall, also in Alpena Township.

Muszynski and police have said both men could be involved in the deaths, but no one has yet been charged.

Check out this interactive timeline of police’s investigation into the deaths of Brynn Bills and Abby Hill. Story continues below timeline.

On Dec. 22, police turned their investigation over to Muszynski for review for possible charges, but would not say who might be charged or with what.

Muszynski has made no decision thus far.

BRYNN BILLS

Friends and family called Bills, of Alpena, a smart, caring, outgoing lover of the outdoors and music.

She was last seen alive in early August. She would have turned 18 on Aug. 12.

Police and the teen’s father, Duane Bills, of Fairview, sought the public’s help in finding the girl beginning Aug. 27. Duane Bills offered a reward that climbed to $20,000 for any information leading to a break in the case.

Acting on a tip, police searched a wooded area behind Wirgau’s home on Naylor Road on Sept. 28 and found Bills’ body, which they identified through tattoo markings.

ABBY HILL

On Oct. 5, police said Hill had gone missing.

On Oct. 16, police said they’d found Hill’s body following a search of a wooded area in Alpena Township the day before. They said it appears Hill died by homicide.

Police say Hill participated in the alleged hijacking with Srebnik and Wirgau on Sept. 21. Hill had been wanted on felony warrants related to the alleged hijacking.

Police had arrested Hill on Sept. 15 — six days before the alleged hijacking — on a warrant for failure to appear for a court matter. They released her the next day, as is typical in such cases.

Hill was Facebook friends with Bills.

JOSHUA WIRGAU

Wirgau worked in the repair shop of the same towing company where his alleged victim in the hijacking case worked.

A judge in 2009 sentenced Wirgau to 43 months in prison for sexually assaulting a girl between the ages of 13 and 15, when Wirgau was 20.

A year before that, Wirgau pleaded guilty to third-degree retail fraud and an unrelated drunk-driving charge.

BRAD SREBNIK

In addition to the current charges related to the alleged hijacking, Srebnik also currently faces felony weapons charges in Osceola County and domestic violence charges in Alpena County.

Before that, Srebnik in 2007 pleaded guilty to charges of conducting criminal enterprises and receiving stolen property.

Several years later, he admitted to serving as an accessory in two 2012 break-ins and thefts of guns and drugs in Montmorency County.

He also has pleaded guilty previously to delivering marijuana.

THE HIJACKING

According to court testimony from the alleged victim, Wirgau on Sept. 21 called his coworker at the towing company to his Naylor Road home for a ride.

When the driver got there, the alleged victim testified, Wirgau got into the passenger seat of the tow truck while Hill and Srebnik, hopped onto the bed of the truck. Wirgau had a handgun, while Hill and Srebnik each had an assault-style rifle, the man testified. The driver had long ago worked with Srebnik and knew Hill from high school, the driver told the court.

In addition to the guns, Hill and Srebnik allegedly carried a big black bag onto the tow truck.

Wirgau allegedly pointed the handgun at the driver for a few seconds, demanded the driver take them to the intersection of Lacomb and Haken roads, and then laid the gun on his lap.

Wirgau appeared skittish and paranoid and started sobbing during the drive.

All three exited the truck when it reached its destination. Wirgau then handed the driver a baggie the driver said contained cocaine and then Srebnik handed the driver a $100 bill through the passenger-side window and told him to tell a female acquaintance he loved her, and demanded the driver leave.

Police on Oct. 6 searched the area near the Lacomb-Haken intersection with a police dog and a helicopter, but police wouldn’t confirm whether that search was related to the alleged hijacking or Bills’ death.

Police arrested Wirgau on Sept. 27 and Srebnik three days later. Both face several charges related to the alleged hijacking.

Srebnik was bound over to 26th Circuit Court for trial on Oct. 25 and Wirgau was bound over on Nov. 10.

THE CONNECTIONS

Here’s what we know about the players in police’s investigation into the two deaths:

* Brynn Bills, 17, of Alpena, was last seen alive in early August. Police found her body Sept. 28 on property on Naylor Road in Alpena Township.

* Abby Hill, 31, was Facebook friends with Bills and, according to police, participated in an alleged hijacking on Sept. 21 with Joshua Wirgau, owner of the Naylor Road property where police found Bills’ body. Police reported Hill missing Oct. 5 and on Oct. 15 found Hill’s body in a wooded area in Alpena Township.

* Joshua Wirgau, 34, owns the Naylor Road property where police found Bills’ body. He also allegedly participated in the Sept. 21 hijacking with Hill.

* Brad Srebnik, 35, It’s unclear whether Srebnik is connected to Bills beyond the fact that police and the prosecutor accuse him of participating in the alleged Sept. 21 hijacking with Wirgau and Hill.

THE TIMELINE

A timeline of major events in the investigation into Bills’ death:

* Early Aug.: Bills goes missing. The exact date isn’t clear. Her father said she was last seen alive Aug. 1, though police have indicated it may have been as late as Aug. 3.

* Aug. 27: Police first report Bills missing and seek the public’s help in finding her.

* Sept. 21: Wirgau allegedly holds a man at gunpoint to demand a ride from Naylor Road to near the intersection of Lacomb and Haken roads. Hill and Srebnik, also armed, are also in the vehicle.

* Sept. 27: Police arrest Wirgau on charges related to the alleged hijacking.

* Sept. 28: Police find Bills’ body buried on Wirgau’s Naylor Road property.

* Sept. 30: Police arrest Srebnik.

* Oct. 5: Police report Hill missing.

* Oct. 6: Police search the area near the Lacomb-Haken intersection.

* Oct. 15: Police find a body they believe to be Hill in a wooded area in Alpena Township.

* Nov. 19: In a court filing, Alpena County Prosecutor Cynthia Muszynski says Srebnik is a suspect in Hill’s and Bills’ deaths, which she calls homicides. Police refuse to comment.

* Dec. 22: Police turn their investigation over to Muszynski for review for possible charges.