MILWAUKEE (CBS 58) — A Milwaukee Public Schools safety worker is facing four felony charges after prosecutors say he sent sexually explicit messages to three current or former middle school students, repeatedly contacted them late at night and, in one case, allegedly offered to buy a teenager shoes in exchange for a "favor."

Antonious J. Partee, 27, is charged with one count of grooming a child for sexual activity involving two or more children and three counts of sexual misconduct by school staff or a volunteer. The grooming charge is a Class D felony carrying a maximum penalty of 25 years in prison and a $100,000 fine. Each sexual misconduct charge is a Class I felony.

According to a 17-page criminal complaint filed Friday, Partee worked as a security guard at Lincoln Center of the Arts Middle School. The school's principal told investigators Partee had worked there for about three years, was assigned to the seventh-grade floor and also served as a mentor and coached girls basketball and track.

The complaint details allegations involving three students, two of whom are 14 and one who is 15.

The investigation began after the father of one former student contacted police in July. The father said his son told him Partee had messaged him on Instagram through an account named "Tone_Partee" and made a sexual comment about the teen's body.

The student told investigators he blocked Partee and deleted the messages. His father later used a backup Instagram account belonging to his son to continue communicating with Partee while pretending to be the teenager, according to the complaint.

The complaint says Partee repeatedly messaged and attempted to call the account during the early morning hours. Investigators said some of the exchanges contained sexual innuendo and references to the teenager's body.

After the father began taking screenshots of the messages, Partee allegedly deactivated his Instagram account.

Investigators subsequently learned of allegations involving other students.

One 14-year-old told detectives Partee began following him on Instagram while he was in sixth grade and started messaging him the following school year. The two later exchanged phone numbers.

The teen said Partee repeatedly called him between 2 and 3 a.m. after the school year ended. Investigators reviewed messages in which Partee allegedly made sexually suggestive comments about the teenager's body.

According to the complaint, records showed Partee made numerous late-night attempts to reach the student, including 15 unanswered calls between approximately 2:36 and 3:18 a.m. on July 10.

Another exchange reviewed by investigators occurred shortly after 2 a.m. July 20. Partee allegedly referred to the boy as his "favorite student" before making sexually explicit comments after the teen sent him a photo in his basketball uniform.

Partee then allegedly attempted to call the teenager eight times between 2:48 and 3:15 a.m.

A third student, also 14, told investigators Partee had been his track and football coach and worked as a security guard at his school.

The teen said Partee first contacted him on Instagram the day he graduated from eighth grade in June. The messages initially referenced track and other school-related topics, but the teen said they later became sexual.

He told investigators that Partee sent messages Aug. 10 that appeared to request sexual acts and repeatedly called him late at night. The teenager described the situation to detectives as "actually scary" and said he worried about experiencing similar behavior from adults at his new school.

The complaint says investigators reviewed messages in which Partee repeatedly made sexual comments to the teen and allegedly told him, "I'll make you feel good."

In another exchange, the teenager asked Partee for money to buy shoes for school.

Partee allegedly responded, "Yeah," before asking, "What you got in return" and telling the teen, "I'll buy whatever" but that he would have to give him "a favor."

When the teenager continued asking what the favor would be, Partee allegedly offered to purchase a pair of shoes and asked what the teen would give him in return.

The exchange continued, with Partee allegedly telling the student he would buy the shoes online so the teen would "have no choice but to see me" to pick them up.

Later, Partee allegedly wrote, "Help me out and I can help you," as the teenager continued asking about the shoes.

Investigators obtained a search warrant for the "Tone_partee" Instagram account and said records from Meta helped establish that Partee was the person operating it.

The complaint says investigators also found messages to another Instagram user in which Partee sent several nude videos of himself, at times showing his face.

Partee was interviewed by investigators Aug. 25 after being advised of his rights.

According to the complaint, Partee confirmed "Tone_partee" was his Instagram account and said he was the only person with access to it. He also confirmed working as an MPS safety worker at Lincoln Center of the Arts and coaching track and girls basketball.

Investigators said Partee referred to himself as a "bad person" multiple times during the interview and said he had a drinking problem that became worse during the summer while he was not working at the school.

Partee allegedly told detectives there were nights when he became intoxicated and communicated with middle school students, then regretted it the following morning.

When questioned about the first student, Partee acknowledged that his messages referred to the child's genitals and admitted the comments were inappropriate, according to the complaint. Investigators said he made similar admissions regarding the second student.

When shown messages involving the third student, Partee allegedly acknowledged that he was messaging the teenager for "sexual advances."

The complaint says Partee then signed and dated an apology letter addressed to the school and his family.