EDITOR'S NOTE: The family's attorney says they were never told to quarantine. Hear what he has to say, here.

FRONTENAC, Mo. (KMOV.com) – The family of the St. Louis County woman who tested positive for COVID-19 broke quarantine and attended a father-daughter school dance Saturday evening at Villa Duchesne, County Executive Sam Page said.

Page said the family was asked to self-quarantine on Thursday, March 5, after the young woman called the county's health hotline and told them her symptoms. However, Page said the father took his other daughter to a father-daughter dinner dance with Villa Duchesne and Oak Hill School (VDOH) at the Ritz-Carlton in Clayton on Saturday.

In a letter to parents, VDOH officials said the father and daughter didn't learn of the diagnosis until after they were already at the dance. They left the dance immediately after.

[READ: Coronavirus in Missouri: Woman in St. Louis County tests positive for COVID-19]

Sunday afternoon, Page said the coronavirus patient has been acting responsibly and maturely but her father “did not act consistently with the health department’s instructions and instead ... he decided to take his daughter to a school function."

Following the first St. Louis County coronavirus patient's timeline A young Ladue woman was diagnosed with coronavirus Saturday, marking the first confirmed COVID-19 case in St. Louis County and the state of Missouri.

Page said the county learned about the father-daughter dance on Sunday and officials told the man "to stay home or they will issue a formal quarantine that will require him and the rest of his family to stay home by the force of law."

Early Sunday evening, John Burroughs School officials sent a letter to parents saying the father and sister of the infected woman attended an event at the home of a Burroughs family on Saturday before going to the dance. Several other people went to the same home that same night. The school said all those people have been contacted.

[READ: Following the timeline for St. Louis County's first coronavirus patient]

"Based on the conversations that I have had with medical experts today, the likelihood of any of the Burroughs students contracting the virus is extraordinarily low," the statement read. "Still, under an abundance of caution, we have asked them to stay home from school until we have more information."

John Burroughs School plans to hold classes as usual this week.

The coronavirus patient returned from Italy to Chicago on Monday. She then took an Amtrak to St. Louis on Wednesday. She called the hotline on Thursday and went to Mercy Hospital on Friday. Doctor Randall Williams, the director of the Missouri Department of Health and Senior Services, said he received a phone call about the positive coronavirus diagnosis at 1 p.m. Saturday.

[WATCH: Dr. Williams speaks about the first coronavirus case in St. Louis County and Missouri]

The dance was scheduled to begin at 6:30 p.m. and Page said the family was informed after the diagnosis between 6 and 6:30 p.m.

Classes at VDOH have been called off for the week since the COVID-19 patient is the older sister of a Villa student.

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Several people called and emailed News 4 with concerns. Some said the father shouldn't have put several people in danger and should've stayed home. Others said the school should call off classes from more than just one day.

Officials from VDOH are urging people who attended the dance to seek appropriate medical treatment if they notice any symptoms and to notify the school.

Chaminade College Preparatory School said students who have family members who attended the dance will participate in classes remotely starting Monday. The school said students who aren't showing any symptoms, can return to school March 23 following spring break.

The Mary Institute and St. Louis Country Day School released a statement Sunday asking its students who have siblings attending VDOH and may have had contact with the patient's family to self-quarantine in their home for the coming school week.

The Archdiocese of St. Louis asked all students, faculty and staff who attended Saturday night's dance to stay home. In a statement, Archdiocese officials said students who fall under this category should call the school Monday morning.

The Ascension Catholic School is working with state and local health officials. The school instructed all students, faculty and staff who had family members who attended the father-daughter dance to stay at home.

News 4 reached out to Ritz-Carlton for a statement.

“We are aware of news reports and have contacted health authorities to obtain their guidance. Meanwhile, we are taking additional steps to perform enhanced cleaning of hotel areas where the event was hosted. The well-being of our guests and associates is of paramount importance. For more information, please refer to Centers for Disease Control and Prevention (CDC) or local health authorities.”

Villa Duchesne and Oak Hill School released the following statement:

Head of School Michael F. Baber announced to school families that Villa Duchesne and Oak Hill School will close for tomorrow as School officials work with local health officials. The school learned this morning that a St. Louis County woman who has received a positive test for COVID-19 is the older sister of a Villa Duchesne student. School officials immediately began gathering information and planning for the safety of our students and families. “We are communicating with the St. Louis County Department of Public Health and sharing everything that we know with them. We will work with officials to ensure we are doing everything possible to mitigate risk and to maintain our safe environment,” says Alice Dickherber, Director of Communications and Marketing. “We are committed to the health and safety of our community and we will follow the guidance of public health officials as we plan for the coming days.”

A Villa Duchesne and Oak Hill School spokesperson later added:

We are always focused on prevention of the spread of germs on campus and will be cleaning tomorrow. Our full-time cleaning and maintenance staff are on campus each day, cleaning and sanitizing throughout the school day. We are cleaning continuously to prevent the spread of germs and we will make sure we are taking direction from public health officials as to any additional measures we should take. Our Spring break begins on Monday, March 16.

For more information on the virus and safety guidelines, visit the CDC’s website at cdc.gov/coronavirus. The St. Louis County Health hotline is 314-615-2660 or visit the county's website at stlcorona.com to learn more.