The authorities cautioned the local population to refrain from entering into contact with the suspect, as he is considered armed and extremely unsafe.
Officials released photos over the weekend of the SUV Jakubowski allegedly burned before leaving the gun shop that was burglarized, along with additional identifying photos.
Authorities have also contacted area school districts to caution them about the search for Jakubowski so they can take precautionary measures, the Rock County Sheriff's Office said.
A fugitive in Wisconsin has more than a dozen guns and a deep-seated hatred of religion and government, authorities warn.
"As the search for Joseph A. Jakubowski (M/W, DOB: 07/21/84, 5'10", 200 lbs, green eyes and brown hair) continues this Sunday night, investigators are continuing to work through the evening to attempt to locate this armed and unsafe suspect.
Jakubowski is believed to be armed and risky, and anyone who sees him is advised to call police and not approach him. Authorities said he might have changed his appearance.
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Tips and any other information related to Jakubowski are still sought by investigators who remind the public that the Federal Bureau of Investigation is offering a $10,000 reward for any information leading to his capture. "Direct sightings should be immediately reported to "911" and general tips or historical information should be directed to 1-800-CALLFBI (225-5324)". You can watch it live on NBC15 and nbc15.com.
More than 150 law enforcement officers were searching for 32-year-old Joseph Jakubowski, said Rock County Sheriff Robert Spoden.
On Tuesday, 16 guns were stolen from Armageddon Supplies on U.S. Highway 14 in Janesville.
Officials also released the image of his vehicle that was set on fire after the burglary.
It was unclear if Jakubowski, who according to local media was unemployed, remains in Wisconsin or if he had left the state. He also reportedly had made threats to steal weapons and use them against public officials or at an unspecified school.
"Our local law enforcement personnel have been collaborating closely with all of the federal and state law enforcement agencies to utilize all available investigative tools to locate Jakubowski", Spoden said.