Donald Ellens, 75, was found killed in his home in the 9000-block of South East End. Police also found Aletha McGee, 62, dead in her house in the 9000-block of South Dobson.
Police say Ellens was found dead Tuesday night from multiple stab wounds after relatives hadn't heard from him for some time.
Neighbors say he often volunteered to cut others' lawns.
"He took very good care of us," said Betty Barry, friend. "We could always depend on him. Even when we got sick or something like that, he would help us out."
"Sunday would have been his birthday," said Eugene Taylor, friend. "This coming Sunday, and we would have had a barbecue on the Fourth of July celebrating the Fourth and his birthday."
Ten minutes after police were called to Ellens' home, officers learned of another death nearby. Police found McGee shot to death in her house after relatives called for a well-being check. Investigators say a broken key was found in the lock of her door.
"I've been calling her every day," said Jerrell Martin, neighborhood trash collector. "I'm calling and calling and get no answer. I came yesterday on the route, and I ring her doorbell. And I don't get an answer. I called her this morning, and I don't get an answer. And it's not like her because she called me back all the time."
Friends say the mother of two and grandmother of six had recently retired from a job at AT&T and was enjoying spending more time with family.
"I would spend my Thanksgivings over here," said Adonis Bell, friend. "She was like a mother to me, a lot of the guys that were from the neighborhood, especially this particular block."
"It just threw me for a loop. I couldn't believe it because she's such a wonderful person," said Loye Macon, friend.
Police say there's no indication the two killings are connected though both victims lived alone.
Neighborhood residents say there's been a rash of recent incidents involving people impersonating repairmen who try to talk their way into the homes of seniors.
"I want to make Chicago my home when I retire, but I'm really thinking, hey, maybe there's a safer place somewhere that you don't have to worry about all of this," said Jimmy Williams, neighborhood resident.
Police say they are still investigating whether anything was stolen from either crime scene. No one is in custody.