Are all aliens released if they are arrested by ICE?

Not all aliens held by ICE are released.  In most cases, ICE requires the alien to see an immigration judge in order to request an immigration bond. At this juncture, it is strongly encouraged that you seek an immigration lawyer to navigate the bond hearing process.  

Also depending on the alien’s criminal history, they may be subject to mandatory detention, which means that they are not eligible to receive a bond. In general, serious crimes involving firearms, drugs, or “crimes involving moral turpitude” (theft, fraud, etc.) are the kinds of crimes that subject an individual to mandatory detention.

In deciding whether someone is subject to mandatory detention or not, the alien’s time in jail is not as important of an issue as other factors that may come into play, such as length of sentence even if it is probation.