- Associated Press - Wednesday, August 17, 2011

MADRID | A young chemistry student working as a volunteer to prepare a visit by the pope to Madrid has been arrested on suspicion of planning a gas attack targeting protesters opposed to the pontiff’s stay, officials said Wednesday.

Pope Benedict XVI is due to arrive Thursday for a nearly four-day visit to celebrate World Youth Day, and a protest march was scheduled for Wednesday evening in Madrid.

A police official said the suspect arrested in Madrid on Tuesday is a 24-year-old Mexican student specializing in organic chemistry. She would not say whether investigators believe the man was capable of carrying out a gas attack, and did not know if the man had chemicals for one.

He was arrested at a Madrid convention center where the hundreds of thousands of pilgrims coming to town for the papal visit are supposed to pick up their accreditation, the police official said on the condition of anonymity in line with the department’s rules.

An official with the visit’s organizing committee said the Mexican was a volunteer working to help deal with the massive flow of people coming to Madrid. The official would not give her name, citing the church-run committee’s policy.

A total of 30,000 people from around the world are taking part in that organizing effort, 10,000 police are providing security in Madrid and organizers say they expect more than 1 million young pilgrims for World Youth Day, which started Tuesday and runs through Sunday.

The Mexican Embassy identified the detainee as Jose Perez Bautista and said he was from Puebla state, near Mexico City.

Police have 72 hours from the time of the arrest to take the detainee before a judge at the National Court for questioning or release him. A court official said he would appear before the judge Thursday at the earliest.

The court official - speaking on the condition of anonymity in line with court policy - said the detainee had been making threats over the Internet against people in Spain opposed to the pope’s visit, and police who had been monitoring his online activity ultimately decided to arrest him as the visit approached.

Church organizers say the papal visit is costing about $72 million to stage. Protesters complain the government is essentially spending taxpayer’s money on the visit by granting tax breaks to corporate sponsors and perks such as discount subway and bus tickets for pilgrims.