TAMPA, Fla. -

The search for two young boys taken from their grandmother near Tampa on Wednesday morning expands across the southeast after their dad's vehicle may have been seen in Tennessee.

Hillsborough County investigators believe the biological father took 4-year-old Cole Hakken and 2-year-old Chase Hakken from his mother-in-law, who was found tied up in her Tampa home.

A statewide Amber Alert issued Wednesday was expanded to other states Thursday after Joshua Michael Hakken's 2006 black GMC pickup truck may have been spotted in Etowah, Tenn., about 8 p.m. Wednesday. 

Believing Joshua Hakken and his wife, Sharyn, may be armed and dangerous, the Tennessee Bureau of Investigation set up a command post and asked that tips be phoned in to 800-TBI-FIND.

The children were taken from their grandmother, who has temporary custody.

Chase Hakken is 3 feet tall, weighs 33 pounds, has brown hair and brown eyes.  He was last seen wearing pajamas. Cole Hakken is 3 feet 9 inches tall, weighs 44 pounds, has brown hair and brown eyes.  He was also last seen wearing pajamas.

Deputies spent Wednesday afternoon and evening at the home of Joshua and Sharyn (pictured right), searching for any clues that might indicate where they would go.

Officials say Joshua Hakken had been arrested in a hotel on multiple drug charges in St. Tammany Parrish, Louisiana, where he had just attended some type of anti-government rally.

At some point after the arrest, the state of Louisiana took custody of both children and placed them in temporary foster care. While the children were at the foster care facility, investigators said Joshua Hakken allegedly showed up at the facility waving a gun and started beating on the front door.

Anyone in Florida with information about Hakkens or who sees the GMC pickup with Florida tag U95-KT is asked to call 911 or to call the Hillsborough County Sheriff's Office at 813-247-8200.