Baker reported he was in the bushes casing out the mansion, at 602 E. South Temple, court documents state.
He also sent texts stating, "i only have 9 clips ak about 300 small arms," and "I hope I do better with the gov im all camoed out they wont see me coming I don't have my vest on so I hope I dont catch one," court documents state.
His texts included a threat to kill a police officer who had driven past the mansion more than once during Baker's period of surveillance, court documents state.
Law enforcement met with the acquaintance, who showed the threatening text messages. Baker was later arrested near the governor's mansion.
A search of Baker's vehicle revealed several dozen rounds of ammunition, court records state. Following his arrest, Baker admitted to placing the ammunition in his vehicle and said he used his cell phone to send texts about the governor.
Police said following Baker's arrest that Herbert was at home during the time Baker was conducting surveillance and was removed from the premises for safety reasons.
Baker's criminal history includes pleading guilty to bank fraud in federal court in 2005. He has also been convicted of a string of felonies in state court, including theft, fraud and drug charges.
Baker will make a first court appearance in federal court next week. He faces up to five years in prison and a $250,000 fine if convicted.
State prosecutors had already charged Baker with a misdemeanor count of threatening elected officials and felony counts of drug and weapons possession in connection with the February incident.
The state case is set for a preliminary hearing April 26 before 3rd District Judge Vernice Trease, but will likely be dismissed in favor of the federal charges.
"We anticipate that the state charges, filed against Baker in February, will be dismissed in the next few days and we will proceed with our federal case," said Melodie Rydalch, a spokeswoman for the U.S. Attorney's Office.