A Louisiana woman, her daughter, her son and his girlfriend have been identified as the four victims killed in a stabbing spree on Saturday that also left a young child critically wounded in the southern part of the state, according to a relative and family advocate.

Verna Mae Verdin, her daughter Letha Verrett, her son Paul Verret, and his girlfriend Krissy Lynn Parfait were stabbed to death at their home in the community of Houma, the relative and advocate, Brandon Thiel, told Louisiana television news station WVUE and said on an online campaign raising funds in part for the victims’ funeral expenses.

The wounded child reportedly was Verdin’s six-year-old grandson, who happened to be spending Saturday night with her.

Local authorities have not formally identified any of the victims of Saturday’s stabbing spree but did say they had detained a 47-year-old man named Kaegan Jude Solet in connection with the case. Thiel told WVUE that Solet had fathered a child with one of the slain victims.

The bloodshed in Houma came about two years after Louisiana’s department of health warned that intimate partner violence was a “significant public health concern in the state”. The state’s rate of women murdered by men has historically been significantly higher than the national average, according to the Louisiana Coalition Against Domestic Violence.

Meanwhile, across the US, more than half of female homicide victims are killed by current or former male intimate partners, Centers for Disease Control and Prevention (CDC) crime data show.

Verdin was planning to retire in two weeks from a 20-year career at Walmart at the time of Saturday’s killings, as Thiel put it to WVUE. Thiel said Letha Verret was a mother herself and had seven children, including three who are minors. Paul Verrett and Krissy Lynn Parfait lived together in a camper behind Letha and Verdin, WVUE reported.

Investigators said on Sunday that deputies with the Terrebonne parish sheriff’s office which patrols Houma initially encountered the wounded child while responding to reports of a “series of stabbing incidents”. Deputies reported that they then found Verdin, the Verret siblings and Parfait dead nearby.

Thiel told WVUE that the boy is a “full of energy, smiling child that [is] just the light of so many of the family’s world”.

“Thankfully, he was able to make it out,” Thiel remarked. He also said, “They are processing a lot right now. They are trying to process the loss of family members.”

Community members rallied around Verdin’s family as news of the killings spread around Houma and beyond. The fundraising campaign Thiel had organized to support covering the slain’s victims’ funeral expenses and medical costs for the wounded boy had exceeded $46,500 by Monday morning.

As of Monday, there had been at least 19 mass murders in the US for the year so far, according to statistics tracked by the Guardian. Two of those mass murders had been reported in Louisiana, including a case in April in which eight children were shot to death in the city of Shreveport in what the police described as a “violent domestic incident”.

A mass murder is defined as a case in which four or more victims are killed. In the US, most such cases are carried out by attackers with guns.

Texas authorities reported a mass murder on Sunday near the community of San Benito. Investigators there said they could not immediately release many details – but they confirmed four adults who were related had been shot to death, and one suspect had been taken into custody, the Texas television news outlet KVEO reported.