A grandfather shot dead his daughter and her six children before taking his own life at a home in Bell, Florida, police have said.
The children range in age from three months to 10 years old, said Gilchrist County Sheriff Robert Schultz.
The authorities have identified the gunman as Don Charles Spirit, 51.
Schultz said a colleague responded to reports of a shooting on Thursday afternoon and on arrival made contact with Spirit before he killed himself.
"I haven't seen anything like this at all," said Schultz.
"This county, this community is going to be devastated from this. It is a small county, we are all family here.
"We're asking for prayers for this community and the families involved."
After Spirit took his own life, police found the other seven bodies in the house, although there were other people there who were still alive.
Spirit, who was known to police previously, was the only suspect, said Schultz.
According to the Florida Department of Corrections, the grandfather was once behind bars for a gun charge, and was released in February 2006.
Bell is a town of about 350 people located 30 miles west of Gainesville.
Multiple shootings in the US have happened in schools, colleges, military institutions, shopping malls and homes. Each time innocent victims die, but this rural community has been shaken by the multiple killing, says the BBC's Tom Esslemont in Washington.
It is likely to reopen a painful debate about gun ownership, but is unlikely to change deeply entrenched polarised views, our correspondent adds.
When Bell, Florida came to my attention, I thought of the 'Liberty Bell' and remembered that it was stolen in America.
The Liberty Bell Museum is in Florida (Validated)
With former King Juan Carlos also being known as Don Juan Carlos, it is impossible to ignore Don Charles 'Spirit' being identified.
With some very weird goings on in our world, it is impossible to ignore that people are being influenced detrimentally to kill people by unseen forces.There are also people who are willing to kill people. The job of being a hired assassin is with being paid really well apparently...We do not see the unseen influences; yet again I have been warned again of intention to harm these days. Trusting in the Lord for His Protection.
No names are given of the deceased.
What we know is the only suspect is killed.
The connection with Florida and England is discovered by name of landmarks. In Thornton Heath where I was born, a few states are named roads including Florida Road. In Bolton where I live now, Orlando Bridge is named over Trinity Street Station and Orlando being in Florida is revealed here. What was also noticed recently - a sign that would have indicated British Rail had a banner over AMCO RAIL
Bolton is in the heart of the Royal Duchy of Lancaster - with Charles being on a Job share with his mother, the Queen does he also share the title Duke of Lancaster too and Co-Head of the Commonwealth Nations? The agendas are planned ahead. Monarch Programming is not named without reason. Too many killings and illegal wars - Satanic Wars.
The Holy Bible identifies the elect Kyria and her children. While unrelated - a woman and her children have been killed. In our world, innocents are being killed in wars too.
Ephesians 6 identifies spiritual wickedness in high places!
"Therefore do not fear them, for there is nothing concealed that will not be revealed, or hidden that will not be known. "What I tell you in the darkness, speak in the light; and what you hear whispered in your ear, proclaim upon the housetops.… Matthew 10:26-27
May the souls of the innocents rest in peace being far away from the evil that has been rising up and prevailing in our world...One day this evil will be destroyed.
Peace be with you