Houston (CNN) Exhausted and drenched in filthy floodwater, weary emergency workers and volunteers scrambled to save the latest wave of Tropical Storm Harvey's victims, amid ongoing flash flood warnings and the threat of continuing rainfall.

One of the victims was Sgt. Steve Perez, a veteran Houston police sergeant who drowned on his way to work.

Perez, 60, left for work in the dark about 4 a.m. Sunday and "spent about 2½ hours driving around trying to get to his duty station," police Chief Art Acevedo said. The 34-year police veteran drove on an underpass.

Perez "died in trying." RIP, sergeant. Houston thanks you and mourns all who have died in #HarveyFlood .

On Monday, officials narrowed the location to one area. The Cajun Navy , a Louisiana-based volunteer rescue force that gained fame in Hurricane Katrina, helped look for Perez, Acevedo said, tearing up.

"Once our dive team got there, it was too treacherous to go under and look for him, Acevedo said. "So, we made a decision to leave officers there waiting until the morning, because as much as we wanted to recover him last night, we could not put more officers at risk."

"For we knew in our hearts it was going to be a recovery mission," Acevedo said.

His body was recovered early Tuesday.

It is with a heavy heart that we announce the tragic in the line of duty death of Sergeant Steve Perez. pic.twitter.com/cHJxjnFgII — Houston Police (@houstonpolice) August 29, 2017

Local officials in Texas have confirmed at least nine Harvey-related deaths. An undetermined number of people are missing, including six family members whose vehicle was swept away in the floods Sunday in northeast Houston.

With another landfall expected, the devastation and misery could intensify.

Latest developments

-- Late Tuesday, Houston Mayor Sylvester Turner issued a midnight to 5 a.m. curfew until further notice. He tweeted the move is meant to prevent property crimes at evacuated homes.

Curfew was used after Hurricane Ike. Prevented burglaries, looting. — Sylvester Turner (@SylvesterTurner) August 29, 2017

-- President Donald Trump met with officials in Austin and Corpus Christi. Trump did not visit the hardest-hit parts of Texas because the President wanted "to be very cautious about making sure that any activity doesn't disrupt the recovery efforts that are still ongoing," White House press secretary Sarah Huckabee Sanders said

-- Several rain gauges southeast of downtown Houston report more than 48 inches of rain from the storm known as Harvey. That marks the most rain ever recorded in the contiguous United States from a tropical storm that made landfall. The previous record was held by Tropical Storm Amelia, which hit Texas in 1978.

-- Houston's George R. Brown Convention Center was hosting more 10,000 evacuees, Turner said. Officials said two additional shelters will house evacuees: The Toyota Center and the NRG Center.

-- Officials will not ask for immigration status or documentation from anyone at any shelter, according to tweets in English and Spanish from the city's verified account

-- Residents within 1.5 miles of the Arkema peroxide plant in Crosby, northeast of Houston, were evacuated as a precaution, the Harris County Fire Marshal Office said. Arkema said the potential for a chemical reaction that can cause a fire or explosion at the site "is real," though it doesn't believe there is imminent danger. The company evacuated a team that has been at the flooded facility since it shut down Friday as Harvey approached.

At least 9,000 to 10,000 rescued

A sea of volunteers and rescue workers used fishing boats and big SUVs to save Harvey's victims. One volunteer even used a dump truck.

Three days after Hurricane Harvey slammed into Texas, the stubborn, slow-moving storm wreaked more havoc when it caused Houston's Addicks Reservoir to overflow and breached a levee in nearby Brazoria County.

Photos: Hurricane Harvey slams Texas Downtown Houston is seen behind the flooded Buffalo Bayou a few days after Hurricane Harvey came ashore in August 2017. The Category 4 storm caused historic flooding. It set a record for the most rainfall from a tropical cyclone in the continental United States, with 51 inches of rain recorded in areas of Texas. An estimated 27 trillion gallons of water fell over Texas and Louisiana during a six-day period. Hide Caption 1 of 22 Photos: Hurricane Harvey slams Texas NASA astronaut Jack Fischer photographed Hurricane Harvey from the International Space Station. Hide Caption 2 of 22 Photos: Hurricane Harvey slams Texas Steve Culver comforts his dog Otis in the hurricane aftermath. Harvey destroyed most of his home in Rockport while he and his wife were there. Hide Caption 3 of 22 Photos: Hurricane Harvey slams Texas Houston police officer Daryl Hudeck carries Catherine Pham and her 13-month-old son, Aiden, after rescuing them from floodwaters. Hide Caption 4 of 22 Photos: Hurricane Harvey slams Texas A damaged home is seen in the Key Allegro neighborhood of Rockport. Hide Caption 5 of 22 Photos: Hurricane Harvey slams Texas A car is submerged by floodwaters on a freeway near downtown Houston. Hide Caption 6 of 22 Photos: Hurricane Harvey slams Texas Melani Zurawski cries while inspecting her home in Port Aransas, Texas. Hide Caption 7 of 22 Photos: Hurricane Harvey slams Texas A graveyard is flooded in Pearland, Texas. Hide Caption 8 of 22 Photos: Hurricane Harvey slams Texas Soldiers with the National Guard patrol Rockport, looking for residents trapped in their homes. Hide Caption 9 of 22 Photos: Hurricane Harvey slams Texas Evacuees are loaded onto a truck in Houston. Hide Caption 10 of 22 Photos: Hurricane Harvey slams Texas People push a stalled pickup through a flooded street in Houston. Hide Caption 11 of 22 Photos: Hurricane Harvey slams Texas Rockport residents return to their destroyed home. Hide Caption 12 of 22 Photos: Hurricane Harvey slams Texas Rescue boats fill Tidwell Road in Houston as they help flood victims evacuate the area. Hide Caption 13 of 22 Photos: Hurricane Harvey slams Texas People wait to be rescued from their flooded home in Houston. Hide Caption 14 of 22 Photos: Hurricane Harvey slams Texas Volunteers in Dallas organize items donated for hurricane victims. Hide Caption 15 of 22 Photos: Hurricane Harvey slams Texas When Harvey slammed the Texas coast and flooded much of Houston, volunteers sprang into action. Some came from as far away as the Florida Everglades, boats in tow, ready to rescue people trapped in their homes. Hide Caption 16 of 22 Photos: Hurricane Harvey slams Texas Larry Koser Jr. and his son Matthew look for important papers and heirlooms inside a flooded home in Houston. Hide Caption 17 of 22 Photos: Hurricane Harvey slams Texas Members of the National Guard rest at a furniture store in Richmond, Texas. Hide Caption 18 of 22 Photos: Hurricane Harvey slams Texas Volunteer rescue workers help a woman from her flooded home in Port Arthur, Texas. Hide Caption 19 of 22 Photos: Hurricane Harvey slams Texas This aerial photo shows flooded residential neighborhoods in Houston. Hide Caption 20 of 22 Photos: Hurricane Harvey slams Texas Tammy Dominguez and her husband, Christopher, sleep on cots at the George R. Brown Convention Center, where thousands of people were taking shelter in Houston. Hide Caption 21 of 22 Photos: Hurricane Harvey slams Texas An elderly patient waits to be rescued from the Gulf Health Care Center in Port Arthur. The facility was evacuated with the help of first responders and volunteers. Hide Caption 22 of 22

"It was scary -- the water was up to here," Houston resident Yee Seng said, gesturing to the middle of her chest.

The floodwater that topped the reservoir deluged her street and turned it into a river. Seng's boyfriend, Steve Konemany, tried to salvage some of her belongings by floating them on an air mattress.

Steve Konemany pushes a mattress with belongings after the Addicks Reservoir overflowed Tuesday.

"We just didn't want to stick around to see what was going to happen," Seng said.

Officials said between at least 9,000 to 10,000 people have been rescued in the Houston region.

Houston police rescued at least 3,000, Acevedo said. The fire department has rescued between 3,000 to 4,000 people, said fire chief Samuel Peña. The US. Coast Guard has rescued more than 3,000 people, according to Lt. Mike Hart.

That number may continue to rise, as countless residents remain trapped in their deluged homes three days later.

"Every passing hour, more boats are getting into the water," Acevedo said earlier. "This is a catastrophic event."

Floodwater overwhelms levee

The floodwater breached a levee in the county south of Houston.

Local rivers swelled to major flood stage, county spokeswoman Sharon Trower said.

"The Brazos River is being pounded, and all of that water is coming down from the tributaries and creeks into the river," she said. "All the roads around us are flooded. We don't have any evacuation routes to tell people to take."

Brazoria County sits between the Gulf of Mexico and Houston, which remains the site of Harvey's most appalling devastation. But Brazoria County's levee breach is not expected to impact the flooding in Houston.

More wrath to come

Tropical Storm Harvey hovered over the Gulf of Mexico and threatened to dump an additional 8-12 inches of rain in eastern Texas and western Louisiana through Wednesday night. Houston could see an inch more.

#Harvey is expected to retreat back to the Gulf of Mexico before heading back toward #Houston Wednesday. #txwx #TropicalStormHarvey pic.twitter.com/32RoWCover — CNN Weather Center (@CNNweather) August 27, 2017

And the water won't stop rising anytime soon. Harvey could bring more "catastrophic and life-threatening" flooding before making landfall again Wednesday morning near the Texas-Louisiana border, according to the CNN Weather Center.

Engulfed home in Spring, Texas

Swollen rivers in east Texas aren't expected to crest until later this week.

Federal officials are already predicting the deadly storm will drive 30,000 people into shelters and spur 450,000 people to seek some sort of disaster assistance.

Stuck in a wheelchair as the water rose

People have turned to the walkie-talkie app Zello to report their dire circumstances. Among them were an elderly couple trapped on a roof and a family caught in the maelstrom with three children, including one in the throes of a seizure and another with autism.

Confined to a wheelchair as the water rose, Karen Preston watched as Harvey's flood took over her home.

Harvey evacuee Karen Preston cries as she is given a pillow at Houston's convention center.

Coast Guard rescuers on water scooters plucked her from the flood and to safety -- but without her wheelchair.

"I can't walk. I just had surgery on my knee," Preston said. "Right now, I'm in so much pain."

She found herself taking shelter at Houston's convention center. Many have no idea whether their homes have been destroyed.

"How do you go from here?" Preston said, choking back tears. "Where do you start? Where?"

Entire Texas National Guard activated

Thousands of calls for help have gone out across Houston, and state, local and military rescue units have plucked thousands of stranded residents from the water and deluged homes.

JUST WATCHED Father and son reunite after Harvey Replay More Videos ... MUST WATCH Father and son reunite after Harvey 08:11

"None of us (is) going to give up," Acevedo said.

The Pentagon is identifying resources, including trucks, aircraft and troops, that can be dispatched for hurricane relief if the request comes, defense officials said. Gov. Greg Abbott activated the entire Texas National Guard, roughly 12,000 Guardsmen, he said Monday.

In Harris County, home to Houston, authorities asked stranded people to hang sheets or towels from their homes so rescuers could spot them more easily.

The scope of how many people are trapped in flooded homes remains unclear.

Rep. Sheila Jackson Lee said she believes the number of trapped residents across Houston could be "tens of thousands."