Sarah Rose Ludemann was a good student. She was nice and a little stubborn. She liked to text friends on her cell phone. She painted her nails the colors of the season. And she was in love.

She could have been any other teenager, except for this: Police say she was stabbed to death by a rival suitor, a 19-year-old woman just a year older than her.

Police say Rachel Marie Wade plunged a kitchen knife into Ludemann about 12:40 a.m. Wednesday - stabbing her in the heart, according to a witness.

The 18-year-old Pinellas Park High School senior died an hour later at Northside Hospital and Heart Institute in St. Petersburg. Wade was arrested soon afterward on a charge of second-degree murder.

Ludemann was the fifth Pinellas high school student to die this past week. Four students died in a crash in Seminole on Friday.

But her death was no accident, police said.

Countless times this past year, Pinellas Park police say, the victim and suspect in the case have been at odds over their on-and-off again boyfriend, Joshua Camacho - a 19-year-old who dated both and fathered a child with a third woman.

It wasn't a love triangle, according to Capt. Sanfield Forseth, but a "love hexagon."

Allegations of stalking, harassment and domestic violence involving victim, suspect, boyfriend and their friends are detailed in many police reports.

"There's so many dynamics, so many people involved," Forseth said. "The one center of gravity seems to be Joshua Camacho."

. . .

Ludemann was a "straight-A" student, friends say.

She and Camacho lived half a mile apart in Pinellas Park.

"That was her first boyfriend," said friend Ashley Lovelady, 17. "That was her first love."

But she was not Camacho's only love.

Several months into their relationship, friends say, Ludemann learned that Camacho impregnated another woman. Months later, Ludemann learned Camacho also was seeing Wade.

Police reports detail several confrontations between the parties in the following months.

On July 2, Ludemann confronted Camacho over his infidelity, according to a police report, and he punched her in the face.

Her mother, Gay Ludemann, declined to prosecute. "But (she) wanted to know how to keep Camacho away from Ludemann," an officer wrote.

Then on July 31, Ludemann and Wade accused each other of road rage. Wade said Ludemann recklessly chased her. Ludemann said Wade rear-ended her. No one was arrested.

The most recent police report is from Aug. 31, when Ludemann told police Wade was harassing her with angry calls. Wade told police Ludemann sent her threatening e-mails.

Ludemann told police "she just wanted it documented in case Wade followed through on her threats."

. . .

Camacho denied being unfaithful. He said Ludemann was his girlfriend. "I was always with her," he said.

But Wade kept texting threats the night before the stabbing, according to Camacho. Those messages led Ludemann to seek out Wade, police say, at a house on 52nd Street where one of Wade's friends lived.

Ludemann had just pulled up in a green minivan, police say, when Wade met her at the driver's side door and stabbed her.

. . .

Police say they found the knife on a nearby roof. Wade, of 12001 S. Belcher Road in Largo, is being held without bond in the county jail.

Her only previous arrest was an April 2008 charge of domestic battery after she was accused of hitting another boyfriend. The charge was later dropped.

Ludemann's family declined to comment.

Her friends gathered Wednesday afternoon along 52nd Street. A memorial of roses, carnations and alstroemeria lilies sat on a nearby lawn.

"I knew that it was just a big mess," said friend Dani O'Leary, 18. "I knew that it was all stupid to begin with.

"But I didn't know it was going to go this far."