An investigation by a House committee into the deadly attacks in Benghazi, Libya, on Sept. 11 found 13 instances of alarming events in the months before the attack that killed four Americans, prompting diplomats to make repeated requests for heightened security.

Those incidents were outlined in a letter to Secretary of State Hillary Clinton on Tuesday, with a request that the State Department reveal whether or not it was aware of these attacks and explain what steps were taken to beef up security.

The Committee wants a response from Clinton by Oct. 8 and a hearing on the issue two days later.

The letter, written by Republicans Darrell Issa, chairman of the House Oversight and Government Reform Committee, and Jason Chaffetz, stated that the earliest attack happened as early as April.

Many of the incidents explained in the letter are not directly related to the U.S. diplomatic presence in the Easrern Libyan city, but one that was especially cause for concern took place in June when Ambassador Chris Stevens -- who later died in the Sept. 11 attack -- was forced to stop his morning run for about a week after a post on a pro-Gadhafi Facebook page broadcast the location of the run and made a threat against him, according to the letter.

“Put together, these events indicate a clear pattern of security threats that could only be reasonably interpreted to justify increased security for U.S. personnel and facilities in Benghazi,” the letter read.

The lawmakers didn’t reveal who their sources for the investigation were, but said they are people have direct knowledge of the events.

“Based on information provided to the Committee by individuals with direct knowledge of events in Libya, the attack that claimed the Ambassador’s life was the latest in a long line of attacks on Western diplomats and officials in Libya in the months leading up to September 11, 2012,” the letter read, adding that repeated requests were made for more security but were denied. The attack “was clearly never, as Administration officials once insisted, the result of a popular protest.”

However, Clinton has said on multiple occasions that the Libya attack was an act of terrorism. She also said that al Qaida affiliates may also be involved. An investigation into the attacks, by the Obama administration, is still underway.

While on his diplomatic mission, Stevens -- an Arabic speaker who was reputed to be a moderate -- was reportedly worried about the security threats in Benghazi, the rising Islamic extremism in the region, and being on al Qaida’s hit list, according to CNN.

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