DALLAS, Texas (CBSDFW) – A 13-year-old boy and his 10-year-old sister were injured early Tuesday morning, after gunmen opened fire at the door of a Northeast Dallas apartment unit.

More than one dozen bullet holes were marked by crime scene specialists at the door and window of one apartment at the Labella Palms Apartments, located in the 9400 block of Royal Lane.

READ MORE: Customs Agents Seize $50K+ In Meth Hidden Under 18-Year-Old's Clothing At Texas/Mexico Border  

“They had fallen asleep, and next thing you know, they start shooting,” Stephanie Davis, grandmother of the shooting victims said Tuesday.

READ MORE: Tarrant County Sheriff’s Office Seeks A&M Kwik Mart Armed Robbery Suspect

The children were inside their apartment with their father. The boy has a gunshot to the head area, and his sister was grazed by a bullet on her back. Davis believes gunmen were looking for someone specific, and mistakenly targeted her family.

“Both of my grandbabies were in there, and my son, and thank goodness everyone made it out alive. (The gunman) thought the person they were looking for was in apartment 1015. They were not. They shot the wrong apartment up”, she said.

MORE NEWS: Texas Among 16 States Backing Alabama's Challenge To Census Privacy Tool

Dallas Police have placed the shooting with Gang Violence detectives. So far, no arrests have been made.