The incident occurred yesterday in Tando Adam Khan town, where residents of Joharabad area attacked a house which they claimed was being used for "illicit activities".
The attack took place after a man brought a "woman of ill repute" to the house located in a residential neighbourhood.
After a mob locked the outer door of the house, the man inside telephoned the owner of the building, Wali Muhammad, for help.
Muhammad arrived at the spot and opened fire, injuring a local resident.
The irate mob then attacked Muhammad and his two companions with sticks, axes and knives.
TV news channels aired footage, apparently shot with mobile phones, that showed the mob beating the men with sticks.
Ghulam Muhammad Bharoro, Wali Muhammad's 50-year-old companion, was killed by the mob while the two other men were seriously injured.
Police registered a case and arrested seven men who were allegedly involved in the incident.
The attack caused considerable tension in the area and shops and businesses remained shut today.
A large number of people attended Bharoro's funeral.
Mirpurkhas Deputy Inspector General of Police Ghulam Haider Jamali has finalised a report on the incident that will be submitted to the Sindh Chief Minister.
