(CNN) The man who publicly accused Philippines President Rodrigo Duterte of running a hit squad and personally killing people won't be given state protection.

Senate President Koko Pimentel announced on his verified Facebook page that Edgar Matobato won't be put in protective custody because his life has not been threatened.

"I've denied the request for protective custody of the witness (Edgar) Matobato because there is no Senate rule to justify it," he said. "There's even no showing that his life or safety is threatened."

Another Philippines Senator called the decision "heartless."

"We'll be tackling this on Monday, but in the meantime we'll just have to find ways to make sure that our witness will be protected," Sen. Sonny Trillanes told CNN Philippines.

'Our work was to kill'

In testimony Thursday, Matobato said he was part of the 300-member "Davao Death Squad" (DDS), which he alleges was run on the orders of Duterte.

"Our work was to kill criminals like drug pushers, rapists, snatchers. Those were the people we killed every day," Matobato said.

Duterte's office denied the claims made by Matobato on Thursday, and said the President was "unfazed" by the Senate investigation.

"The Duterte administration is committed to a platform of a peaceful, crime-free, corruption-free nation that is not affected by any controversy," presidential spokesman Ernesto Abella said.

Unreliable witness?

Some have called Matobato's testimony into question, including Duterte's son Paolo -- the current Vice Mayor of Davao City.

Matobato said in his testimony that Paolo Duterte ordered the killing of Richard King, a billionaire businessman over a woman.

The King family's legal counsel, Deolito Alvarez, called the accusations "completely false" in a text message to CNN.

"I am convinced that the accused who are facing the charge in court are the perpetrators," he said. "The statement of witness Matobato in trying to cast cloud and put politics into the equation is not true."

Paolo Duterte responded in a statement, saying "What de Lima and this certain Matobato say in public are bare allegations in the absence of proof. They are mere hearsay. I will not dignify with an answer the accusations of a madman."

Photos: Rodrigo Duterte has said some outrageous things. Speaking at a business forum in Manila in December 2016, Duterte admitted killing suspected criminals during his time as mayor of Davao City. Hide Caption 1 of 17 Photos: Rodrigo Duterte has said some outrageous things. The day after Trump won the US presidential election in November 2016, Duterte said he and Trump share some traits. Hide Caption 2 of 17 Photos: Rodrigo Duterte has said some outrageous things. After reports emerged of a potentially blocked arms sale, Duterte told CNN Philippines in November 2016 that he would turn to Russia for weapons. Hide Caption 3 of 17 Photos: Rodrigo Duterte has said some outrageous things. During a state visit to China in October 2016, Duterte announced his economic and military 'separation' from the US. Hide Caption 4 of 17 Photos: Rodrigo Duterte has said some outrageous things. In October 2016 Duterte expressed growing hostility with the US president. Hide Caption 5 of 17 Photos: Rodrigo Duterte has said some outrageous things. After US president Barack Obama said he would raise extrajudicial killings in a meeting with Duterte, the Philippines President responded angrily on September 5, first in English then in Tagalog. As a result, Obama canceled the meeting. Hide Caption 6 of 17 Photos: Rodrigo Duterte has said some outrageous things. As he addressed troops at the country's Armed Forces Central Command Headquarters on August 5, Duterte recounted U.S. Secretary of State John Kerry's visit to the country, saying in Tagalog that he was feuding with U.S. Ambassador to the Philippines Philip Goldberg. Hide Caption 7 of 17 Photos: Rodrigo Duterte has said some outrageous things. The Philippines president-elect effectively said he supported vigilantism against drug dealers and criminals in a nationally televised speech in June 2016. Hide Caption 8 of 17 Photos: Rodrigo Duterte has said some outrageous things. Foreign diplomats weighing in on Rodrigo Duterte's controversial remarks did not sit well with the then-mayor. Hide Caption 9 of 17 Photos: Rodrigo Duterte has said some outrageous things. Duterte apologized to the Pope after cursing him for the traffic he caused during a 2015 Papal visit to the Philippines. Hide Caption 10 of 17 Photos: Rodrigo Duterte has said some outrageous things. In September 2016, Duterte likened himself to the Nazi leader and announced that he wants to kill millions of drug addicts. Hide Caption 11 of 17 Photos: Rodrigo Duterte has said some outrageous things. Speaking at a press conference to unveil his new cabinet on May 31 2016, Rodrigo Duterte said journalists killed on the job in the Philippines were often corrupt. Hide Caption 12 of 17 Photos: Rodrigo Duterte has said some outrageous things. During the third and last presidential debate, Duterte had said that he would plant a Philippine flag in disputed territories should China refuse to recognize a favorable ruling for the Philippines. Hide Caption 13 of 17 Photos: Rodrigo Duterte has said some outrageous things. Duterte made international headlines in April 2016 with his inflammatory comments on the 1989 rape and murder of an Australian missionary that took place in Davao City. Hide Caption 14 of 17 Photos: Rodrigo Duterte has said some outrageous things. He also lashed out at the womens' group that filed a complaint against him before the Commission on Human Rights (CHR). Hide Caption 15 of 17 Photos: Rodrigo Duterte has said some outrageous things. At a CNN Philippines Townhall event in February 2016, Duterte, admitted that he had three girlfriends and a common-law wife. His marriage to Elizabeth Zimmerman was annulled due to his womanizing, but he denied this meant he objectified women. Hide Caption 16 of 17 Photos: Rodrigo Duterte has said some outrageous things. Although he later denied the accusations, the former Davao City mayor admitted his links to the alleged Davao death squad in a May 2015 broadcast of his local television talk show. Hide Caption 17 of 17

'Systematic failure'

A 2012 investigation by the Commission on Human Rights found that from 2005 until 2009, "there was a systematic practice of extrajudicial killings, which can be attributed or attributable to a vigilante group or groups dubbed in the media as the Davao Death Squad."

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It also found there was a "systematic failure on the part of local officials to conduct any meaningful investigation into said killings," and recommended that a local ombudsman investigate whether Duterte was criminally liable for "his inaction in the face of evidence of numerous killings committed in Davao city and his toleration of the commission of these offenses."

The report noted that there was a "dearth of evidence" to conclude that local police or local government was directly complicit in the extrajudicial killings.

Duterte's war on drugs

Duterte has come under increasing international criticism for his war on drugs.

Philippines National Police chief Ronald dela Rosa told CNN that as of 8 a.m. local time Friday, 2,035 deaths were under investigation -- though not all were classified as drug related -- and 1,105 people had been killed in police operations.

Testifying before the Senate committee on August 23, dela Rosa said that local police "follow the rule of law," and that there was no shoot-to-kill order despite the growing toll of bodies piling up in the wake of Duterte's crackdown.

Duterte came into office with huge public support after he vowed to clean up the country of drugs and corruption.