They are many reasons why an employer will treat certain employees a certain way. Some employers may expect more from certain employees for one reason or another or have different job requirements. This is not by itself illegal and for the most part employers can set their own internal policies for work performance, attendance and other expectations. However, there are some exceptions to this rule.
Employers are not allowed to make policies that discriminate against employees due to them being in certain protected classes. Also, employers cannot make different rules or treat an employee differently because they reported a violation of the law, participated in an investigation or filed a complaint against the company. If employers do this it is considered whistleblower retaliation and the employer may be liable to compensate the employee for doing so.
There are many different actions which can be considered retaliation against an employee though. Some are obvious such as terminating the employee or demoting them, but there are many other actions employers cannot do as well. The employer cannot take any actions against an employee that are materially adverse in order to deter employees from exercising their protected rights.
Examples of these actions could be warnings or reprimands, poor evaluations, transferring the employee to a less desirable position or location, holding the employee to higher standards for attendance and other rules of the company, threatening deportation or other civil threats and many other types of actions.
There are many employees in California who have made complaints against their company or participated in investigations against the company. Employees who do this are protected from any retaliation from the employer for doing so. This retaliation can come in many different forms though and it is important for employees to understand their rights. Experienced attorneys understand what employers can and cannot do and may be a useful resource.
Source: www.eeoc.gov, "Questions and Answers: Enforcement Guidance on Retaliation and Related Issues" accessed on March 8, 2018