It’s one of the most terrifying crimes that can happen to anyone – a violent home invasion in the dead of night.

And as of Sunday night, Buffalo Police were investigating four such crimes committed over a period of six days.

All four incidents involved men with guns who terrorized people after breaking into their homes late at night.

“We are trying to determine if there is any connection between these incidents. At this point, we don’t know,” said Chief of Detectives Dennis J. Richards.

“We do ask people in the community to be vigilant and alert. If you hear something unusual, such as loud noises or a door being broken down at a neighbor’s house, call 911 immediately.”

In the latest incident, a man broke into a home in the 200 block of Colvin Avenue shortly before 2 a.m. Sunday. The intruder pointed a silver handgun at the home’s male occupant and robbed the man of a brown paper bag that, according to the victim, contained $24,000 cash.

In the Colvin home invasion, the suspect was described as a black male with dark skin tone and “a bumpy face,” police said.

Buffalo police have reported three other home invasions since Christmas night:

• Sometime between 8:40 and 9 p.m. Christmas night, two armed men wearing hoodies forced their way into a home in the 100 block of Farmer Street, near Tonawanda Street and Hertel Avenue. The men demanded money and then left the home and fled into the neighborhood. Police have not said whether anything was stolen. A man and woman who were in the home were not injured. The attackers were described by police as two young black men, one about 22 and the other about 25.

• About 12:30 a.m. Saturday, three men – one carrying a shotgun – kicked in an apartment door in the 1000 block of Grant Street, terrorizing two female occupants. The men searched the apartment and demanded that the occupants show them the attic. They, too, escaped empty-handed. The three intruders wore black clothing with hoodies and skull caps, police said.

• About 2 a.m. Saturday, three attackers broke into a home in the 300 block of West Delavan Avenue, where they robbed and terrorized three men and three women. Police said the three male victims were clubbed on the head with a shotgun, and one of the female victims suffered cuts to her head when she tried to escape by crashing through a window.

The bandits took cash and jewelry from several of the victims, police said.

“They did not hurt my daughter, but they scared the hell out of her,” said the father of one of the female victims. “They made them all lay on the floor and stay quiet.”

One of the attackers on West Delavan had a shotgun, and the other two had handguns, police said.

While the numbers are sporadic, city police generally investigate several home invasion crimes each month, said Richards.

“Sometimes the intruders are looking for drugs or money. It happens fairly often that they are looking for something that is not there, but they think it might be there,” Richards said.

Anyone with knowledge of any of the crimes is asked to call the department’s TIPCALL line at 847-2255.

Some home invasion crimes in Buffalo and its suburbs have shaken the community in recent years.

Just over a month ago, on Nov. 24, a 96-year-old man was badly beaten and robbed by intruders who broke into his home on Longview Avenue, on the city’s East Side. Police are still investigating the attack on Levi Clayton, a popular church deacon and World War II veteran.

The attackers, including two men with handguns, took jewelry and guns from Clayton’s home and caused a lot of damage looking for other items, police said.

Clayton was treated in Erie County Medical Center for a broken jaw and other injuries. ECMC said Sunday night that he is no longer a patient there.

“I know he has been doing better since the attack,” said the Rev. James E. Giles, pastor of Greater Works Deliverance Fellowship Church and an active member of the Stop the Violence Coalition. “I know the police are still looking for the guys.”

In Giles’ view, there appears to have been a recent “spike” in such crimes in recent months, which he attributed to “desperate times” in the local economy.

“Desperate times usually result in a spike in crimes like this. That’s an act of desperation to break into someone’s home and rob him like that. … You can wind up doing a lot of time for something like that,” Giles said Sunday night.

In a home invasion crime that turned to murder, Rochie Jones III, 28, of Cheektowaga, was sentenced last month to 17 years in state prison. He was convicted of manslaughter and weapons possession in connection with the November 2011 shooting death of Armod Law, a liquor store owner who was killed in his home on West Grand Boulevard in Cheektowaga.

Edward McCloud, 41, of Buffalo, has been convicted of second-degree murder in the Law killing, and he faces a possible sentence of 25 years to life, authorities said.

Law, 37, was shot in the head with a semiautomatic handgun, and intruders used duct tape to bind another person in the home, who was not injured, police said.