(CNN) -- A hacker publicly posted Wednesday the home addresses and other information of all 102 police officers with San Francisco's Bay Area Transit system, the second hacking incident against one of its websites since Sunday, a spokesman said.
The website for the BART Police Officers Association was broken into Wednesday morning, and the names and phone numbers of its entire membership were also posted publicly on the Internet, BART spokesman James K. Allison said.
The officers association, or union, took down their website after the hacking incident, Allison said.
It wasn't clear Wednesday who was to blame for the latest hacking incident.
In the prior hacking incident on Sunday, members of the well-known hacking group Anonymous took credit in online messages for breaking into a link off BART's website, and information from BART's internal network was posted, including phone numbers of hundreds of people.
BART has been at the center of controversy about shootings by its officers, the latest being last month that resulted in the death of Charles Hill, 45.
BART officials denounced Wednesday's hacking.
"We condemn this latest attack on the working men and women of BART," interim general manager Sherwood Wakeman said in a statement. "We are deeply concerned about the safety and security of our employees and their families. We stand behind them and our customers who were the subject of an earlier attack. We are deeply troubled by these actions."
Meanwhile, protestors are planning to hold demonstrations next Monday at BART's Civic Center subway station, and transit system officials are planning to beef up security, Allison said.
"We're getting prepared to keep our customers safe as always," Allison told CNN.
Last Thursday, protestors tried to organize a public demonstration, but BART officials cut off cell phone signals at some subway stations "as one of many tactics to ensure the safety of everyone on the platform," officials said.
But the decision to cut cell service was criticized by civil liberty organizations, the San Francisco Chronicle's editorial page and others.
The August 11 protests never materialized.
After the transit system's shut down cell phone signals, Anonymous threatened in a news release and related Twitter pages that it would make a cyberattack Sunday on the BART website.
Then, on Monday night, BART officials temporarily opened and closed downtown subway stations to stem the threat of spreading protests, with police officers in riot gear standing at the Civic Center station.
Only small groups of protestors gathered on the streets to criticize BART and its officers' shooting incidents.