This story was last updated on Sept. 16 at 12:25 p.m. ET.
A 14-year-old boy has been arrested in Texas after a homemade clock he brought to school was mistaken for a bomb.
Ahmed Mohamed brought the clock into MacArthur High School in Irving, Texas, where it was spotted by another teacher who alerted police.
His father fears the incident happened because of his son's Muslim background.
The Irving Police Department dropped and closed the case on Wednesday, saying there was no evidence of intent to create harm. This was the device in question:
Police say the reaction would have been the same no matter who brought it to school #wfaa pic.twitter.com/TrnFxATzO7— D Fernandez (@DemondFernandez) September 16, 2015
Mohamed explained his love of engineering, and how he was arrested, to The Dallas Morning News.
He created the clock in around 20 minutes, according to the Dallas Morning News, using a circuit board and a power supply wired to a digital display, with a tiger hologram for decoration. When he showed it to his engineering teacher, he said, "I would advise you not to show any other teachers," according to Mohamed.
After it beeped in another lesson, he showed the contraption to another teacher who confiscated it. He was then later led into a room with four police officers, and eventually taken to a juvenile detention centre.
I expect they will have more to say tomorrow, but Ahmed's sister asked me to share this photo. A NASA shirt! pic.twitter.com/nR4gt992gB— Anil Dash (@anildash) September 16, 2015
A police spokesman, James McLellan, said that Mohamed wouldn't give a "broader explanation" for what the clock was for.
Mohamed's father, Mohamed Elhassan Mohamed, said: “He just wants to invent good things for mankind. But because his name is Mohamed and because of Sept. 11, I think my son got mistreated.”
Daniel Cummings, the school's principal, sent the following letter (PDF) to parents on Tuesday:
Dear Parents/Guardians,
In Irving ISD and at MacArthur High School, your child’s safety and well-being is always our top priority and we want to maintain open, honest and timely communication with you. If there was ever an imminent threat to your child, we would take immediate and necessary precautions, and we would inform you immediately.
While we do not have any threats to our school community, we want you to be aware that the Irving Police Department responded to a suspicious-looking item on campus yesterday. We are pleased to report that after the police department’s assessment, the item discovered at school did not pose a threat to your child’s safety.
Our school is cooperating fully with the ongoing police investigation, and we are handling the situation in accordance with the Irving ISD Student Code of Conduct and applicable laws. Please rest assured that we will always take necessary steps to keep our school as safe as possible.
I recommend using this opportunity to talk with your child about the Student Code of Conduct and specifically not bringing items to school that are prohibited. Also, this is a good time to remind your child how important it is to immediately report any suspicious items and/or suspicious behavior they observe to any school employee so we can address it right away. We will always take necessary precautions to protect our students.
Thank you for your understanding and support of MacArthur High School as we do everything we can for your child's safety.
Mohamed's story has been shared across social media, with #IStandWithAhmed trending in the UK and U.S.
I don't know how to build a clock. We need kids like Ahmed around to build clocks for us. #IStandWithAhmed— Kumail Nanjiani (@kumailn) September 16, 2015
In solidarity with @IStandWithAhmed CAIR-Chicago staff brought our clocks to work too. #IStandWithAhmed pic.twitter.com/NK9CWhyfru— CAIR-Chicago (@cairchicago) September 16, 2015
Brought my clock to work today. #IStandWithAhmed #Solidarity pic.twitter.com/h4Jr0siF1A— Simran Jeet Singh (@SimranColumbia) September 16, 2015
Ahmed and us at the Robotics Competition in Dallas #IStandWithAhmed pic.twitter.com/SkI3I8DDo8— مرام (@queen_hijabi_) September 16, 2015
He responded to the hashtag on Wednesday morning.
Thank you for your support! I really didn't think people would care about a muslim boy. #Thankyouforstandingwithme #IStandWithAhmed— Ahmed Mohamed (@IStandWithAhmed) September 16, 2015