The attacker struck shortly after a meeting at the office regarding security in Taloqan, the capital of Takhar province, had finished. The Taliban claimed responsibility in what was its latest example of high-profile target selection.
The police chief, General Mohammed Daoud Daoud, was a key figure in Afghanistan's recent history. A former military commander of Ahmad Shah Massoud's Northern Alliance, he oversaw the siege of Kunduz, the final major battle of the US-led invasion that followed the September 11 attacks in 2001.
A former deputy interior minister, when he was the top counter-narcotics official in Afghanistan, Daoud had accused the Taliban of profiting from the opium trade by forging an alliance with drug smugglers and taxing farmers.
He also served at one point as governor of Takhar, reportedly at the request of the British, who considered him the country's cleanest governor.
The commander of NATO forces for northern Afghanistan, German general Markus Kneip, survived today's attack, suffering slight injuries, defence minister Thomas de Maiziere, who confirmed the two fatalities, told reporters in Berlin.
Three other German troops were wounded, he said.
A provincial government spokesman said four Afghans, including General Daoud, were killed and that the governor Abdul Jabar Taqwa was wounded.