NAIROBI, Kenya - A widow of a Pakistani journalist who was shot dead by police in Kenya after he fled arrest in his home country filed a lawsuit against Kenyan police on Monday, her lawyer said.

Arshad Sharif, a strident critic of Pakistan's powerful military establishment and supporter of former premier Imran Khan, was shot in the head when Kenyan police opened fire on his car in October last year.

The complaint was filed by Javeria Siddique and two journalist groups in Kenya against top police and legal officials over the "arbitrary and unlawful killing" of Sharif and the respondents' "consequent failure to investigate".

"It has been a year that I have been fighting for justice," Siddique, one of Sharif's two wives, told AFP last week.

"The Kenyan police admitted that they killed my husband but never apologised."

Her lawyer confirmed the petition had been lodged at Kenya's High Court on Monday, a year to the day since the late-night shooting at a roadblock on the outskirts of the capital Nairobi.

"Yes. The case has been filed," Ochiel Dudley told AFP in Nairobi.

Last year, Kenyan officials said Sharif's killing was a case of mistaken identity and officers believed they were firing on a stolen vehicle involved in an abduction.

Siddique, however, alleges her husband was killed in a "targeted attack".

"I have written to the Kenyan president and foreign minister but they were not even kind enough to say sorry," she added.

'Criminal cover-up'

The petition alleged that the incident had not been investigated at all or "if there have been any investigations, they have not been prompt, independent, impartial, effective, accountable" nor led to the prosecution of the culprits.

"Petitioners fear that the failure to investigate, arrest or prosecute the police officers who unlawfully shot and killed Arshad Sharif amounts to a criminal cover-up," it said.

Sharif fled Pakistan in August last year, days after interviewing a senior opposition politician who said junior officers in Pakistan's military should disobey orders that went against "the will of the majority".

Tens of thousands of mourners attended  Sharif's funeral at Islamabad's main mosque.

'Financial and emotional losses'

Pakistan has been ruled by the military for several decades of its 75-year history and criticism of the security establishment has long been seen as a red line.

Pakistan’s top court has taken note of the murder but the case is still pending.

In December, a fact-finding team of Pakistani intelligence officials submitted a report to the Supreme Court calling the incident a "planned, targeted assassination" that purportedly involved "transnational characters".

Press freedom campaign groups have called for those responsible to face justice.

Pakistan is ranked 150 out of 180 countries in a press freedom index compiled by Reporters without Borders, with journalists facing censorship and intimidation.

"Throughout the past year, I have endured financial and emotional losses and have even been subjected to character assassination," Siddique said.

Police in Kenya are often accused by rights groups of using excessive force and carrying out unlawful killings.

Last year, President William Ruto disbanded a feared 20-year-old police unit accused of extrajudicial killings and the government has said it is embarking on reforms of the security sector.