HOUSTON -- Authorities in central Texas found two more bodies along flooded streams Sunday, bringing the death toll from flooding the state to six.

It's unclear whether a body found in Travis County near Austin is one of the two people still missing in Texas. An 11-year-old boy is still missing in central Kansas, too.

The latest flooding victim identified by authorities was a woman who died when the car she was riding in was swept from the street by the flooded Cypress Creek about 1:30 a.m. Sunday, Kendall County sheriff's Cpl. Reid Daly said.

The car, with three occupants, was in Comfort, about 45 miles north of San Antonio. The driver made it to shore, and a female passenger was rescued from a tree. But Daly said 23-year-old Florida Molima was missing until her body was found around 11 a.m. Sunday about 8 miles downstream. She becomes the sixth flood-related death in Texas this Memorial Day weekend.

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The body of a National Guardsman who had gone missing after a haunting Facebook post was found downstream from where his overturned truck had been located earlier.

Darren Charles Mitchell, 21, from Navasota, had called his family on Thursday to say he was trapped in flood waters on Highway 105 just outside Brenham, reported CBS affiliate KHOU in Houston.

A truck belonging to Darren Mitchell sits overturned and partially submerged in floodwaters on Friday, May 27, 2016 near Brenham, Texas. KHOU

"(My brother) just said he was all right and he made it out of the truck," Ro Mitchell said.

However, shortly after, he posted a picture on Facebook showing floodwaters rising outside his truck, along with a now-tragic message.

A photo posted to Facebook on Thursday, May 26, 2016 by Darren Mitchell, who was missing amid flash flooding near Brenham, Texas. KHOU

Lashandoe Smith, who said she watched in horror when Mitchell's truck was swept into the water, filled in the blanks Friday when she returned to the scene.

"And he got out of his truck, he got in the bed of his truck, he got back out, on top of his truck, and then all of the sudden he got back in his truck. And like maybe 10, 15 minutes after he was in his truck, it just flipped and he topsided into the water," Smith said as she choked back tears. "It just disappeared. Once it flipped, you didn't see tires, his truck, nothing. It just tumbled over."

Darren Mitchell. KHOU-TV

In Bandera, about 45 miles northwest of San Antonio, an estimated 10 inches of rain overnight led to the rescues of nine people. The rain caused widespread damage, including the collapse of the roof of the Bandera Bulletin, the weekly newspaper, KSAT-TV in San Antonio reported. Photos from the area showed campers and trailers stacked against each other, but no injuries were reported.

Torrential rains caused heavy flash flooding in some parts of the U.S. over the last few days, and led to numerous evacuations in southeast Texas, including two prisons. But the threat of severe weather has lessened over the long Memorial Day holiday for many places, though Tropical Depression Bonnie continued to bring rain and wind to North and South Carolina.

Near Austin, a crew aboard a county STAR Flight helicopter found a body Sunday on the north end of a retention pond near the Circuit of the Americas auto racing track, which is close to where two people were reported to have been washed away by a flash flood early Friday, Travis County sheriff's spokesman Lisa Block said. The body still must be recovered and no identification has been made.

To the southeast along the rain-swollen Brazos River near Houston, prison officials evacuated about 2,600 inmates from two prisons to other state prisons because of expected flooding, Texas Department of Criminal Justice spokesman Jason Clark said. Inmates in a low-level security camp at a third prison in the area are being moved to the main prison building, Clark said.

All three prisons are in coastal Brazoria County, where the river empties into the Gulf of Mexico.

"TDCJ officials continue to monitor the situation and are working with our state partners as the river level rises," Clark said, noting that additional food and water has been delivered to prisons that are getting the displaced inmates and sandbags have been filled and delivered to the prisons where flooding is anticipated.

Another prison that's about 70 miles northwest of Houston saw a brawl between inmates and correctional officers on Saturday that began when flooding caused a power outage. Clark estimated as many as 50 inmates in the 1,300-inmate prison were involved.

Some rivers could reach record levels in the next few days, prompting several rural counties between Austin and Houston to call for evacuations.

Hundreds of residents including Kurt Whiteman have been forced from their homes.

"I've been here 20 years, and this is the worst I've seen it," he told CBS News' Mireya Villarreal.

The rising water in several Houston-area rivers and creeks prompted Harris County officials on Saturday to ask about 750 families in the Northwood Pines subdivision to voluntarily evacuate their homes and apartments. Officials also warned residents living near the west fork of the San Jacinto River, north of Houston, that rising waters were likely to flood homes, even those that are elevated, Sanchez said.

"The skies are clear and things look good. But we want to make sure people understand that we are not out of the woods yet. We have to keep an eye on water that's coming through our bayou system," said Francisco Sanchez, a spokesman for the Office of Emergency Management in Harris County.

In Kansas, the search for the missing 11-year-old resumed Sunday and expanded beyond the swollen creek he fell into Friday night, according to Wichita Fire Department battalion chief Scott Brown. "We are more in body-recovery mode than rescue," Brown said Saturday night.

Four people died from flooding in rural Washington County, Texas, located between Austin and Houston, where more than 16.5 inches of rain fell in some places Thursday and Friday. The bodies of two missing motorists were found Saturday in separate parts of the county, according to Judge John Brieden.

Tropical Depression Bonnie reached the South Carolina coast early Sunday, bringing heavy rain and rough tides to an area packed with tourists for the Memorial Day weekend. Forecasters say up to 8 inches of rain have fallen in parts of southern South Carolina. About 3 inches of rain fell in Charleston in 24 hours and more is expected, according to the National Weather Service.