<div id="subtitle">4th envelope with white powder found at UC Irvine, 3 previous letters found to be harmless</div><div><p>An envelope with the same markings and white powder found to be harmless in three other cases has been found on campus at the University of California, Irvine.</p><p>University spokesman Tom Vasich said Tuesday the return address on all four envelopes is in Idaho. Each contained a letter with the words "Black Death."</p><p>Vasich says the assistant dean of biological sciences and a computer sciences counselor opened the letters addressed to them Tuesday, prompting the evacuation of two offices in the natural sciences and computer sciences buildings.</p><p>Two other buildings were evacuated Monday when two professors opened similar letters. The substance inside has not been identified.</p><p>Vasich says the only thing the four targeted employees have in common is that they are women.</p><p>THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.</p><p>IRVINE, Calif. (AP) — Authorities have determined that white powder sent to three people at the University of California, Irvine is not hazardous.</p><p>Two professors received the powder Monday in envelopes with the words "Black Death" written on them. A third envelope was received Tuesday in the computer sciences building. It wasn't immediately clear who was the recipient.</p><p>University spokeswoman Cathy Lawhon said Tuesday the substance hasn't been identified, but tests show it is harmless.</p><p>Parts of a social sciences building, an engineering tower and the computer sciences building were evacuated after the envelopes were received.</p><p>University officials sent an e-mail alert to students, faculty and employees, warning them to be cautious of opening suspicious mail.</p><img src="http://admatch-syndication.mochila.com/images/ad.gif?aid=66306886&bid=informcom" /></div><div id="copyright"><div>

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