Diena Thompson told NBC's "Today Show" her family is doing "a little bit better" after detectives charged 24-year-old Jarred Mitchell Harrell with premeditated murder Friday.
Diena Thompson said she goes through a gamut of emotions and that the pain is excruciating.
She also said she thinks it would be fair for Harrell to get the death penalty.
Somer Thompson's body was found in a Georgia landfill two days after she disappeared in October.
Harrell has also been charged with lewd and lascivious battery and sexual battery.
Harrell was already being held on child porn charges in a separate case.
MORE ON CRIMESIDER
February 12, 2010 - Somer Thompson Murder: Person of Interest Jarred Harrell Arrested with Child Porno
January 22, 2010 - Somer Thompson Murder: Mom Warned a Year Before 7-Year-Old's Abduction
November 4, 2009 - Reward Now $45K to Find Somer Thompson's Killer
October 29, 2009 - Sheriff: Help Me Catch Somer Thompson's Killer
October 27, 2009 - Somer Thompson Funeral: Little Girl Laid to Rest as Sky Fills with Purple
October 27, 2009 - More Than 1,000 Tips But No Leads in Somer Thompson Murder
October 26, 2009 - Somber Sendoff for 7-Year-Old Somer Thompson, Florida Girl Who Vanished After School
October 23, 2009 - Somer Thompson Pictures: Her Mother Vows Justice, A Community Vows Never to Forget
October 23, 2009 - In Somer Thompson Murder, Local Sex Offenders No Longer Suspects, Say Cops
October 23, 2009 - Somer Thompson's Mom to Killer: "We're Coming For You"
October 23, 2009 - How Police Found Somer Thompson and How They Hope to Catch Her Killer
October 22, 2009 - Somer Thompson Body Likely Found, Says Florida Sheriff
October 21, 2009 - Search for Missing 7-Year-Old Somer Thompson Leads to Body in Landfill
October 20, 2009 - Somer Thompson Vanished After School, Seven-Year-Old Girl Missing in Orange Park, Fla.