Over a dozen colleges including Delhi University's prestigious Lady Sri Ram College, Hansraj College and Ramjas College received bomb threats on Thursday but nothing suspicious was found after thorough searches, officials said, a day after a similar e-mail sent alarm bells ringing in the North Block.

A Delhi Fire Service (DFS) official said they first received a call at 4.38 pm about the bomb threat at the LSR College and two fire tenders were pressed into service. Later, other colleges also made the call to authorities.

The local police, a bomb disposal squad, a bomb detection team arrived at the LSR College along with a dog squad and conducted searches but nothing suspicious was found, the official said.

LSR Principal Suman Sharma told PTI the entire campus has been sanitised.

"We received the bomb threat e-mail in the afternoon today. Immediately, the police were informed and they sent a bomb (disposal) squad. The search operation went on for two-three hours and the entire campus has been sanitised," Sharma said.

A police officer said along with LSR over a dozen of other colleges in Delhi received a similar kind of threat as the sender - rizer111rizer@beeble.com - marked them in the CC of the e-mail with subject line "Bomb in the University".

These colleges include -- Hansraj College, Gargi College, Ramjas College, Zakir Husain College, Indraprastha College For Women, Lady Irwin College, Kirori Mal College, Bhaskaracharya College, Deen Dayal Upadhyaya College, Sri Venkateswara College, and PGDAV College.

Apart from DU colleges, Delhi Pharmaceutical Sciences and Research University, School of Planning and Architecture (SPA), among other state universities also received the threat.

The officer said the "beeble.com" is a Europe-based mailing service company, which was earlier used in sending similar kind of threats to schools and hospitals in Delhi and other parts of country.

The content of the threat read, "There's a bomb inside of your university, but also inside of every Delhi University. Blood will scatter everywhere and we will slit your families' throats as well." "The group Terrorizer111 is behind this massacre," the mail reads.

The officer further said that all the affected college campuses were searched but nothing suspicious was recovered from any of them.

Over the past few weeks, bomb threat emails have been received by many establishments in the national capital, including schools and hospitals. Delhi's Chacha Nehru Hospital received a bomb threat on April 30 while more than 150 schools got threats from a Russia-based mailing service company on May 1.

Twenty hospitals, the IGI Airport and the Northern Railways' CPRO office in Delhi received bomb threats through emails from a Cyprus-based mailing service company on May 12.

Seven Delhi hospitals and the Tihar Jail received bomb threats from the same Cyprus-based mailing service company on May 14. The MHA officer received The Delhi Police is conducting investigations into the email bomb threats.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.