Jakubowski allegedly broke into the Armageddon Supplies gun shop in Janesville Tuesday at 8:40 p.m. and stole about 16 high-end firearms.
"I can tell you that we don't know where Mr. Jakubowski is", Sheriff Moore said.
It was later confirmed an assault-style rifle was among the items stolen. Elworthy stressed that the concern was not related to the Janesville gun store robbery and manhunt. Authorities say the fire and the burglary are connected.
Jakubowski became the prime suspect in the burglary of Armageddon Gun Shop after a vehicle registered to his name was found burning on a rural road about three miles from the store within a half hour of the break-in.
Jakubowski's last known address is 811 Glen St.in Janesville. "Police describe Jakubowski as a white male, 5'10", green eyes, brown hair.
A statewide crime alert says Jakubowski "has been highly agitated recently regarding a variety of political issues".
Reports also show Jakubowski made threats to use the weapons against unspecified public officials and schools.
Joseph Jakubowski is no stranger to law enforcement.
Schools in Beloit, South Beloit, Edgerton, Evansville, Ft.
Whitewater Unified School District Administrator Mark Elworthy noted that all schools were involved in a lockdown as a result of the notification by Whitewater police that was unrelated to the "soft lockdown" that previously had been in effect due to the Janesville incident.
Anyone with information about Jakubowski's location is asked to contact the Rock County Sheriff's Office, 608-757-7911.
As of this morning, Beloit and Clinton schools will remain open but on soft lockdown.
Public schools in Janesville and nearby Milton canceled classes Friday as officers combed the surrounding county.
Parents in Beloit could choose to not send students to school this morning, according to school district officials, and Beloit police are at all city schools, command staff confirmed. Some went into a lockdown.
Schools across the area ordered soft lockdowns, and tactical units from the Federal Bureau of Investigation and ATF were called in to help.