SOUTH BEND — A 72-year-old man had a knife held to his throat during a home-invasion robbery Saturday morning.

It was the second violent in-home robbery to take place in the city in less than 48 hours.

Police said Saturday morning’s robbery happened shortly after 4 a.m. in the 1000 block of West Dubail Avenue on the city’s southwest side.

The home’s 72-year-old owner told police that he was lying on the couch watching television when he heard the sound of glass breaking in his dining room.

The homeowner went to the room and found an unmasked man — described as a black male, 6 feet tall, about 25 years old with a thin build and wearing a dark sweatshirt with a diamond pattern on — who demanded money and displayed a knife.

The victim said the robber then grabbed him and held a knife to his throat, threatening him and demanding cash.

The 72-year-old man said he then threw his wallet on the floor, and the robber let him go.

The robber grabbed the wallet and a set of car keys sitting on an end table. Police said the man then left through the broken dining room window and fled in an unknown direction. The man’s vehicle was not stolen.

The victim told police his wallet contained $225 from a recently cashed check and items that included his personal identification. He was not injured in the robbery and required no medical attention.

Police said it does not appear Saturday morning’s robbery was related to a similar robbery Thursday, which happened in northeast South Bend, near Notre Dame.

In that robbery two masked men, one armed with a gun, entered a home in the 1300 block of White Oak Drive about 5:30 a.m., eventually tying up two of the home’s occupants with rope. The men reportedly stole two plasma screen televisions and two laptop computers.

Police are continuing to investigate both robberies, but no arrests have been made in either case.