Story highlights Two Ciudad Juarez bus drivers were slain last month by an unidentified woman

Shooter reportedly sent e-mails saying the killings were to avenge women raped by drivers

Some drivers, fearful of being shot, have not shown up for work

Commuter: "Of course we're afraid. ... but we still have to get to our destination."

She calls herself "Diana, the Hunter." Authorities say the elusive woman has killed at least two bus drivers in Ciudad Juarez, Mexico.

According to the Chihuahua state attorney's office, the unidentified woman, with either hair dyed blond or wearing a blond wig, shot and killed a city bus driver identified as Jose Roberto Flores Carrera, 45, on August 28.

Another bus driver, Fredy Zarate Morales, 32, was killed the next day. In both cases, officials say, "Diana, the Hunter" boarded the buses and shot the drivers point blank.

After the second shooting, several media outlets in Ciudad Juarez reported receiving an e-mail from a sender claiming to be the killer. In the e-mail, she calls herself "Diana, the hunter of drivers."

She reportedly says in the e-mails that her motive is retaliation against bus drivers who have raped vulnerable women, especially those who work in the "maquiladoras," or foreign assembly plants (mainly American) on the Mexican side of the border.

"I'm an instrument that will avenge [the attacks against] several women," the e-mail is reported to say. "We seem weak to society, but we're truly not. We're courageous and, if they don't show respect to us, we will make them respect us by our own means. We women of Juarez are strong."

Arturo Sandoval, a spokesman with the Chihuahua state attorney's office, told CNN the end doesn't justify the means.

"Nobody can take justice into their own hands," Sandoval said. "If she was a victim of a bus driver or knows someone in that situation, she has to report it and let authorities do their job."

The Chihuahua state attorney's office released a sketch of the suspect Wednesday and asked for the public's help to catch her.

"The sketch was done after interviewing more than 20 people who witnessed the homicides and who gave us very valuable information for this investigation," authorities said in a statement.

According to local media reports, citing official sources, authorities know the perpetrator is a woman because she yelled at the second victim before shooting him: "You guys think you're real bad, don't you?"

The slayings have terrorized many bus drivers, especially those operating Route 4, also known as the Yellow Route, which serves main thoroughfares and downtown Ciudad Juarez, a city of 1.5 million located across the border from El Paso, Texas.

Thirty drivers normally cover the route, but many have decided not to show up for work since the second slaying. Julian Vazquez, a bus driver on the same route, is one of those still behind the wheel, although he admits he's afraid.

"There's only about 50% of us working," Vazquez told CNN. "We're full of fear after learning this person killed two of our colleagues and nobody has any clue."

This situation has left hundreds of riders stranded. Others have been forced to look for transportation alternatives for their daily commute.

"Of course we're afraid," commuter Maria Banuelos, said. "We fear that the driver might be attacked or that I will be in harm's way, but we still have to get to our destination."

Ciudad Juarez gained international notoriety in the late 1990s and early 2000s after a wave of slayings involving women. The victims, mainly young, single women, would disappear, their bodies later found in shallow graves in desert areas around the arid city. According to an Amnesty International report, 370 young women and girl were killed in Ciudad Juarez between 1993 and 2005. Most of the slayings remain unsolved.

Mexicans are very familiar with La Diana Cazadora, as it's known in Spanish. A stone monument of the Roman goddess, nude, long-haired and holding a bow, stands on Mexico City's Reforma Avenue, a major thoroughfare. A replica was erected in Ciudad Juarez.