Medecins sans Frontieres (MSF), called Doctors Without Borders in English, pulled out of Afghanistan last year, after more than 20 years, citing lack of progress in an investigation into the killing of their workers on a remote road in the northwestern province of Badghis last June.
   
Interior Ministry spokesman Lutfullah Mashal said on Wednesday the police chief of Badghis's Qadis district was arrested last week on suspicion of involvement in the killings.
   
Arrested on suspicion

"He has been brought to Kabul for investigation. No concrete evidence against him has been found so far, but there is a suspicion he might have been behind the plot," he said.
   
Mashal declined to name the officer, but said his arrest was the result of information from some of the four or five other suspects arrested since the crime. 
   

"There is a suspicion he might have been behind the plot"

Lutfullah Mashal,
Interior Ministry

Three foreign MSF staff - a woman from Belgium and men from Norway and Holland - were killed in June along with two Afghan workers on a remote road in Badghis which, until then, had been considered a relatively safe area.
   
Their vehicle was attacked by gunmen who also used grenades, and initial suspicions focused on the Taliban which has targeted aid groups in its insurgency. 
   
Foreigners targeted

Mashal said of the motive: "It looks like it was a criminal act, but it is still under investigation."
   
Dozens of aid workers, including foreigners, have been killed since US led forces overthrew the Taliban in late 2001 and the violence has greately curtailed humanitarian work in the provinces by international relief agencies.
   
Earlier this month, an Italian woman working for the Care International aid agency was released after being held hostage for more than three weeks by kidnappers in Kabul.
   
Her abduction was a further blow for Afghan President Hamid Karzai and his US-backed government as it struggles to impose its authority while battling the Taliban as well as widespread crime and corruption.