OKLAHOMA CITY — A man who was spotted taking unusual photos of a memorial to Oklahoma City bombing victims and who warned his sister in Iran that hundreds more people would die has been arrested on a complaint of threatening to kill with explosives.

Amiremad Nayebyazdi, 32, was being held Tuesday in Oklahoma County jail without bail, according to records.

A court affidavit said police received a tip Thursday from a longtime friend of Nayebyazdi that the suspect had left a phone message for his sister in Iran saying “hundreds are going to die in Oklahoma City.”

In the message, Nayebyazdi said, “Don’t tell mom and dad until after it is seen on the news,” the affidavit said.

Nayebyazdi, who has a degree in petroleum engineering and worked for an oil company in Oklahoma City, was spotted at the Oklahoma City National Memorial on several occasions taking photos of “unusual angles and places where people didn’t normally take photographs,” the affidavit said. The memorial is to remember the 168 people who were killed in the Oklahoma City bombing in April 1995.

Police, FBI and the bomb squad searched Nayebyazdi’s apartment and his vehicle on Thursday, but no explosives were found. Police said he admitted leaving the message for his sister and that it forewarned of an explosion, but he denied making any explosive devices.