Via VOA: Police Officer Guarding Polio Team Shot Dead. Excerpt:
Police in northwest Pakistan say gunmen have attacked police officers who were guarding a team of polio vaccination workers, killing one of the officers and wounding another.
Officials say the police were attacked Saturday in Peshawar, the capital of the Khyber Pakhtunkhwa province.
No group has claimed responsibility for the attack.
I haven't found this report in the Pakistani English-language media.