The bodies of two youths, who appeared to be Baloch, were found near the railway lines in Saudabad on Tuesday.
Police quoted the witnessed as saying that some unidentified men threw the bodies from a car and escaped.
Separately, the body of a woman was found in Malir River.
Police said that some people saw the body and informed the police about it.
The police fished out the body with the help of rescue workers. A police official said that the victim, who appears to be in her early 20s, was killed some four days ago and had torture marks on her the body. The identity of the victim could not be ascertained till this report was filed.
Similarly, the body of an unidentified 22-year-old man was found in Block-2 of Gulistan-e-Jauhar.