The FBI has released 11 chilling portraits drawn by a man who claims to be the most prolific serial killer in U.S. history so they can try and identify some of his victims.

Samuel Little, 78, has confessed to 90 murders committed between 1970 and 2005 across the entire country.

Little, who is serving a life sentence for murder in a Texas prison, drew the sketches of his victims from memory in his jail cell.

The 11 sketches released on Wednesday have been added to a collection of 16 others that Little drew back in February and the FBI has asked the public for help in identifying them. Some of those have since been matched to open cases.

Samuel Little, 78, has confessed to 90 murders committed between 1970 and 2005 across the entire country. He is currently serving a life sentence for murder in a Texas prison

The chilling drawings include details such as the color of a victim's eyes or hair, as well as jewelry she was wearing at the time she was killed.

One of the sketches shows a white female, aged 45, who was killed in Kendall, Florida back in 1973.

Another drawing depicts a 26-year-old white female killed in 1983 or 1984 in Atlanta, Georgia.

Authorities are actively working to match Little's confessions with evidence from women who turned up dead in states from California to Florida over his 35 year killing spree.

Law enforcement have so far been able to corroborate more than 40 of the 90 murders he has confessed to.

Little, a 6ft 3in former boxer, mainly targeted drug addicts and prostitutes during his decades-long coast-to-coast murder spree and many of his victims were never identified.

The FBI released 11 sketches on Wednesday of victims Little drew in his prison cell. Among them is: A black female age 23 killed in Savannah, Georgia in 1984 (left) and a white female, age 26, killed in 1983 or 1984 in Atlanta, Georgia (right)

Pictured left is a black female, age 22, killed in 1971 in Miami, Florida - her name is possibly Linda. Pictured right is a white female age 45 killed in 1973 in Kendall, Florida - the victim is possibly called Sarah and could be from Massachusetts

Pictured left: Black female, age 28, killed between 1977 and 1982 in Charleston, South Carolina. Pictured right: Black female, age 28, killed in 1971 or 1972 in Miami, Florida - victim possibly worked on Homestead Air Force Base

Pictured left: White female killed in 1982 in New Orleans. Pictured right: Black female killed in 1974 in Cincinnati, Ohio

Pictured left: Black female killed in 1992 or 1993 in North Little Rock, Arkansas. Pictured center: Black female between 22-23 years old killed in 1974 in Savannah, Georgia. Pictured right: Black female, whose name is likely Sarah, killed in 1973 in New Orleans

He usually strangled his victims and many of the deaths were not investigated as homicides but were attributed to drug overdoses, accidents or natural causes.

Little's run-in with the law date back to 1956 with a series of shoplifting, fraud, drug and breaking and entering charges.

But authorities only recently began unraveling his serial killing spree after he was arrested at a homeless shelter in Kentucky in 2012 and extradited to California to face drug charges.

When he was in custody, authorities found DNA evidence linked him to three cold case murders in Los Angeles between 1987 and 1989.

The three women had all been beaten and strangled with their bodies dumped in an alley, a dumpster and a garage. Little was sentenced in 2014 to life in prison for the three murders.

Meanwhile, the FBI had been working on a full background check of Little and found links to other murders that he may have committed.

Pictured left: Black female between 35-40 years old killed in 1981 in Atlanta, Georgia. Pictured right: Black female between 35-45 years old killed in 1977 in Pascagoula, Mississippi - she worked at Ingalls Shipyard

Pictured left: White female, possible named Ann, killed in 1997 in Phoenix, Arizona. Pictured right: Black female, age 24, killed between 1987 and the early 1990s in Monroe, Louisiana

Pictured left: White female killed in 1984 in Covington, Kentucky. Little says he met the victim in Columbus, Ohio and disposed of her body in Northern Kentucky. Pictured right: Black male, age 18, killed in 1971 or 1972 in Miami. Victim possibly called Mary Ann or Marianne

Pictured left: Black female killed in 1976 or 1977 in Wichita Falls, Texas. Body disposed of somewhere outside of Wichita Falls. Pictured right: Hispanic female in her 40s. Killed in 1988 or 1996. Victim possibly from Phoenix where she was killed

Pictured left: Black female between 25-28 years old killed between 1976 and 1979 or in 1993 in Houston Texas. Pictured center: White female between 20-25 years old killed in 1972 in Prince George’s County, Maryland. Pictured right: Black female between 28-29 years old killed in 1984 in West Memphis, Arkansas

They found a link to a murder in Odessa, Texas and had Texas Rangers come to California to interview him in May last year in prison.

The FBI said Little was trying to get moved out his prison and agreed to talk if he could be relocated.

He ended up being indicted in the Odessa murder and was extradited to Texas a few months later.

He gave authorities of list of the 90 women and the name of the city in which he killed them. Little also started drawing his victims for authorities.

The FBI said Little can recall his victims and the killings in great detail but he is hazy on the exact dates.

Little grew up in Ohio, dropped out of high school and lived a 'nomadic life,' shoplifting or stealing to buy alcohol and drugs.

He was accused of murdering women in Mississippi and Florida in the early 1980s but was not convicted.

The FBI said Little is currently in poor health and will likely remain in the Texas prison where is now until he dies.

They say they are working to identify his victims and provide closure and justice in unsolved cases. To report potential case links to Samuel Little, contact ViCAP at 800-634-4097.

Little's run-in with the law date back to 1956 with a series of shoplifting, fraud, drug and breaking and entering charges. He was sentenced in 2014 for murder after DNA evidence linked him to three cold case murders in Los Angeles between 1987 and 1989