She's gruff, and doesn't smile much. She's been a cop in San Francisco for 27 years. She's seen a lot of murder, mayhem, domestic disputes and drugs deals.
But her police work is not about locking up bad guys -- as far as she's concerned, most deserve what they get. Her mission is to protect the vulnerable.
"All I care about is children, old people and animals," she said the other day at her desk in the Mission Station. "People make fun of me. When a call comes in dealing with kids or animals, I'm out the door like a shot."
Nothing illustrates this as well as the story of the rat.
It happened about 3:30 p.m., just after shift change. A lot of officers were coming and going from the station, at 17th and Valencia streets. The back door, which opens to the parking lot where the patrol cars are parked, was open. One of the officers was trimming the bushes along the wall next to the door.
And out came a rat.
Big, fat, furry rat. Big, brown, beady-eyed rat with big teeth and claws, probably carrying God-knows-what kind of vermin and disease.
The rat, faced with too many big cops blocking his escape, cut left. Right through the open back door and into the station.
If a parolee on meth had come in that door, the officers probably wouldn't have jumped and run the way they did when the rat burst on the scene. Grown men with guns jumped and ran. Others grabbed rakes and brooms and tried to corner the pesky critter. Several female officers ran upstairs and watched the mayhem from a balcony over the lobby.
Lucas, who supervises cops on the street, heard the commotion and left the sergeant's office. She saw the animal and went into protect mode.
She waded into the melee and backed off her fellow officers. "It's just trying to get away," she yelled. "Don't hurt it. Just get it out the door."
Which is what they did. Eventually.
"The story of the rat gets blown out of proportion," she said. "I grew up on the south side of Chicago. It's not that I love rats. I just didn't see the point in killing it."
But no one was really surprised that the sergeant wanted to save a rat. Her love of animals runs deep. She is the soft-touch who puts flyers on the Mission Station bulletin board for people wanting to place pets in good homes.
Lucas' tender feelings about animals stem at least partly from her work as a cop -- protecting people. Mistreating animals is often a precursor to violence against other people, especially in domestic disputes.
Many years ago, she said, a friend was having a hard time with her husband. They would fight, and he would hold her cat out a window, threatening to drop it down an air shaft until the woman was reduced to tears.
"I told her, 'You're next.' " Lucas said. "He was doing that to show his power over her. Eventually, he started beating her."
Lucas has a lot of stories about violence toward animals and kids.
A young boy once called 911 from the Valencia Gardens housing project to say his mother had beaten his puppy.
"We got there and found this little boy sitting on the front steps, sobbing," Lucas said. "His mother went to jail and he was on his way to foster care. A bunch of us from the Mission Station called all over the city to find a foster home that would take both the boy and his dog. We didn't want them to be separated.
"I didn't think we could do it. That's highly unusual. We made a lot of phone calls and begged and begged and begged."
And finally found one.
Lucas is single, and lives with a one-eyed dog named "Princess Babaloo," rescued from Death Row at a pound in Visalia (Tulare County).
Lucas knows a lot about animal shelters. She volunteers one day a week at San Francisco's Animal Care and Control at 15th and Harrison streets. She's one of about 250 volunteers who keep the city-financed shelter running.
At the shelter, people call her "sarge." She works with the shelter's veterinarian, Dr. Bing Dilts, as a sort of an unofficial veterinarian technician in training. She can't do a lot of the stuff a vet tech can do, like give shots or insert catheters. But she can hand over instruments during surgeries, keep on eye on monitors and, most importantly, restrain animals while the doc does her stuff.
"Carri is very pro-animal," Dilts said, emphasizing "very."
Lucas walks through the shelter's cage rooms, showing a visitor the dogs, cats, birds, bunnies, fish, lizards, chickens and quail that have been brought in. She stops at every cage and inspects the paperwork, noting the animal's name and disposition, where it was found and who brought it in.
She doesn't like that so many indicate that the animal was brought in by its owner.
"Hmmm. Doesn't match the furniture," she mutters.
Lucas says nothing more, but there is a hint of anger in her eyes. Pets are family, in her mind. You don't send them away. They're vulnerable and innocent. You help the innocent, and protect the vulnerable.
Even if it's a rat.
Chronicle reporter John Koopman and photographer Brant Ward are "embedding" with the San Francisco Police Department.
Their stories appear weekly in the Monday paper.
E-mail John Koopman at firstname.lastname@example.org.
Sgt. Carrie Lucas tries to coax the beast off a ledge. Chronicle photo by Brant Ward