A 52-year-old man has been charged in relation to the two deliberately lit fires outside the Radio 6PR and WAtoday offices on Sunday.
He will face court on Saturday.
The WAtoday HQ on Hay Street was evacuated just after 10am on Sunday morning after two fires were lit near a storeroom exit and emergency fire door at the entrance of the building.
At the time there were concerns the fires were racially motivated, after weekend presenters Jo McManus and Bob Maumill finished a heated debate about Islam just before the fire alarm went off.
But police told station management on Thursday afternoon they were confident the fires had nothing to do with the Islam discussion.
After the fires were extinguished, Mr Maumill said he hoped they were not racially motivated.
"Now I have no evidence to suggest the two are connected.. .if anything lets just hopes it's coincidental," he said.
Mr Maumill said he and producer Rob Fletcher made sure everyone was evacuated before the pair left the building.
"Rob Fletcher and I walked down the fire exit stairs and we were going to go out the fire escape entrance onto Hay Street, but when we got there the whole tunnel was full of smoke," he said.
"We had to do a u-turn and Rob and I turning is like a semi-trailer turning...we did a u-turn and went out the main entrance where a larger fire had taken place which the fireys had extinguished."
Radio 6PR commercial director Barrie Quick said security at the station would be reviewed after the fire.
Firefighters investigated the arson attack, deliberately lit using an accelerant.
"When we have two fires and no other obvious means of igniting them it looks as if someone had deliberately set these fires," station officer Darren Martin said.
"When we arrived one of the fires was spreading. It could have caused thousands of dollars of damage."
Anyone with information is asked to call Crime Stoppers on 1800 333 000 or make a report online at www.crimestopperswa.com.au.
